Managerial Accounting — 2022

KNEC Diploma in Supply Chain Management, Module III. Original examination questions with explained answers for revision. Answers are independently prepared for study and are not an official KNEC marking scheme.

July 2022

Paper codes: 2903/305; 2906/305; 2907/305; 2926/305; 3103

Question 1(a) — 8 marks

Explain four functions of Managerial Accounting in a business organisation.

Answer

  1. Planning: prepare forecasts, budgets and cost estimates that turn objectives into measurable resource requirements.
  2. Decision support: compare relevant future revenues and costs of alternatives such as making or buying, pricing and investing.
  3. Control: compare actual results with budgets, investigate significant variances and recommend corrective action.
  4. Performance evaluation: report controllable results for responsibility centres so managers can assess efficiency and achievement of targets.

Question 1(b) — 12 marks

Hamza Limited manufactures and sells product HM20. The following information relates to the company for the year 2020.

Item Amount
Production (units) 18,000
Sales (units) 15,000
Direct materials (Ksh) 864,000
Direct labour (Ksh) 360,000
Variable production overheads (Ksh) 144,000
Fixed production overheads (Ksh) 120,000
Administration costs (Ksh) 70,000

Additional information: (I) Selling price is Ksh 100. (II) Variable selling overheads per unit amounted to Ksh 3. (III) There was no opening stock. Prepare income statement, using the marginal costing technique.

Answer

Item Working Result
Variable manufacturing cost 864,000 + 360,000 + 144,000 1,368,000
Variable manufacturing cost/unit 1,368,000 ÷ 18,000 76
Closing inventory 3,000 × 76 228,000
Marginal income statement (Ksh) Amount
Sales: 15,000 × 100 1,500,000
Variable production cost 1,368,000
Less closing stock -228,000
Variable cost of goods sold 1,140,000
Variable selling: 15,000 × 3 45,000
Contribution 315,000
Fixed production overhead 120,000
Administration 70,000
Profit 125,000

Question 2(a) — 8 marks

Explain four assumptions of a simple queuing model.

Answer

  1. One service channel handles customers from a single waiting line.
  2. Arrivals are independent and random, normally represented by a Poisson process with a constant mean rate.
  3. Service times are independent and exponentially distributed with a constant mean service rate.
  4. For the usual steady-state M/M/1 results, the service rate exceeds the arrival rate; customers normally follow first-come, first-served discipline.

Question 2(b) — 12 marks

The following information relates to the performance of five students in two examinations, Mathematics and History.

Student Mathematics (%) History (%)
A 80 50
B 60 60
C 90 40
D 50 90
E 80 60

Using the method of ordinary least squares, determine the:

(i) regression equation;

(ii) marks scored in History by a student who scores 78% in Mathematics.

Answer

Mathematics (%) x History (%) y x² xy
80 50 6,400 4,000
60 60 3,600 3,600
90 40 8,100 3,600
50 90 2,500 4,500
80 60 6,400 4,800
Σ 300 27,000 20,500
Item Working Result
Totals n=5; Σx=360; Σy=300
Slope b [5 × 20,500 − 360 × 300] ÷ [5 × 27,000 − 360²] -1.018519
Intercept a [300 − (-1.018519 × 360)] ÷ 5 133.333333
Regression equation ŷ = a + bx ŷ = 133.333333 + (-1.018519)x
Prediction at x=78 133.333333 + (-1.018519 × 78) 53.89

This is an estimated History percentage from the fitted relationship, not a guaranteed individual score.

Question 3(a) — 10 marks

The following is the summarized income statement of Bundix Limited for the year ended 31 December 2020.

Item Ksh
Sales (1,000 units) 12,000,000
Less costs (25% variable) 8,000,000
Profit 4,000,000

(i) Calculate the: (I) break even point in units and in shillings; (II) margin of safety in units and in shillings.

(ii) Determine the number of units that should be sold in order to make a profit of Ksh 5,000,000.

Answer

Item Working Result
Price per unit 12,000,000 ÷ 1,000 12,000
Variable cost/unit 8,000,000 × 25% ÷ 1,000 2,000
Fixed cost 8,000,000 × 75% 6,000,000
Contribution/unit 12,000 − 2,000 10,000
Break-even units 6,000,000 ÷ 10,000 600
Break-even sales 600 × 12,000 7,200,000
Margin of safety units 1,000 − 600 400
MOS sales 400 × 12,000 4,800,000
Units for target profit (6,000,000 + 5,000,000) ÷ 10,000 1,100

Question 3(b) — 10 marks

Maxim Limited has four branches located in Nairobi, Mombasa, Kisumu and Nakuru. The firm engages four companies, A, B, C and D, to install computer systems in the four branches. Each company is assigned to one branch. The fees charged by each company, in thousands of shillings, is as shown below:

Company Nairobi Mombasa Kisumu Nakuru
A 840 700 420 560
B 700 420 350 840
C 210 490 630 420
D 560 490 280 560

Determine the:

(i) assignment schedule that will minimize costs;

(ii) total minimum cost.

Answer

Apply the Hungarian method. Reduce each row by its smallest entry, then reduce each column by its smallest entry.

After row reduction:

Nairobi Mombasa Kisumu Nakuru
A 420 280 0 140
B 350 70 0 490
C 0 280 420 210
D 280 210 0 280

After column reduction:

Nairobi Mombasa Kisumu Nakuru
A 420 210 0 0
B 350 0 0 350
C 0 210 420 70
D 280 140 0 140

Choose four independent zeros, with one assignment in every row and column. Read the values from the original table:

Assign To Ksh ‘000
A Nakuru 560
B Mombasa 420
C Nairobi 210
D Kisumu 280
Minimum 1,470

Minimum cost = Ksh. 1,470,000.

Question 4(a) — 8 marks

Explain four functions of budgets in a business organisation.

Answer

  1. Planning: quantify expected activities, income, expenditure and financing requirements before operations begin.
  2. Coordination: reconcile sales, production, purchasing and cash plans so departments work from consistent assumptions.
  3. Communication and responsibility: tell managers their targets and the resources authorised to achieve them.
  4. Control and evaluation: compare actual results with the budget, investigate variances and take corrective action.

Question 4(b) — 12 marks

Lakut Limited intends to invest in the following projects.

Project Initial investment (Ksh) Total PV of inflows (Ksh)
A 1,300,000 900,000
B 1,600,000 2,100,000
C 1,700,000 1,770,000
D 900,000 950,000

(i) For each of the projects, calculate the profitability index (PI).

(ii) Rank the projects in order of profitability index (PI).

Answer

  1. Profitability index = total present value of future cash inflows ÷ initial investment. Rank B, D, C, A, from highest to lowest PI.
  2. B, D and C have PI above 1 and positive NPV; A has PI below 1. If capital is restricted, the final investment combination also depends on the budget and project divisibility, neither of which is supplied.
Project PI working PI NPV (Ksh) Rank
A 900,000 ÷ 1,300,000 0.6923 -400,000 4
B 2,100,000 ÷ 1,600,000 1.3125 500,000 1
C 1,770,000 ÷ 1,700,000 1.0412 70,000 3
D 950,000 ÷ 900,000 1.0556 50,000 2

Question 5(a) — 8 marks

Randip Limited has two divisions: K and L. Division K expects to earn a profit of Ksh 100,000 on an investment of 5,000,000 while Division L expects to earn a profit of Ksh 1,500,000 on an investment of Ksh 10,000,000. The shareholders’ required rate of return is 16%.

(i) Determine the Residual Income (RI) of the two divisions.

(ii) Based on the results in (i) above, advise the management on the most profitable division.

Answer

  1. Division L is better on residual income because its shortfall is Ksh. 100,000, compared with K’s Ksh. 700,000. However, neither division earns the shareholders’ required return, since both residual incomes are negative.
Division Profit (Ksh) Capital charge: 16% × investment Residual income (Ksh)
K 100,000 800,000 -700,000
L 1,500,000 1,600,000 -100,000

Question 5(b) — 12 marks

Mwanzu Traders is in the process of preparing a cash budget for the year 2022. The following estimates have been provided:

Item Dec 2021 Jan 2022 Feb 2022 Mar 2022 Apr 2022
Purchases (Ksh) 40,200 70,800 29,520 36,080 34,500
Sales (Ksh) 38,400 40,200 48,300 36,900 45,100
Wages (Ksh) 14,000 14,000 14,000 18,000 18,000

Additional information: (I) All purchases and sales are made on credit. (II) Creditors are paid 25% in the month of purchase and the balance in the month following. (III) Debtors pay 50% in the month of sale and the balance in the month following. (IV) Wages are paid in the month they are incurred. (V) An office printer costing Ksh 8,000 is to be bought in February 2022. (VI) The cash balance as at 1 January 2022 is expected to be Ksh 100,500. Prepare a cash budget for each of the months of January, February and March 2022.

Answer

Cash budget (Ksh) January February March
Opening cash 100,500 77,950 39,720
50% current sales 20,100 24,150 18,450
50% prior sales 19,200 20,100 24,150
Total receipts 39,300 44,250 42,600
25% current purchases 17,700 7,380 9,020
75% prior purchases 30,150 53,100 22,140
Wages 14,000 14,000 18,000
Printer 0 8,000 0
Total payments 61,850 82,480 49,160
Net cash movement -22,550 -38,230 -6,560
Closing cash 77,950 39,720 33,160

Question 6(a) — 10 marks

The following table shows the weekly sales, in thousands of shillings, made by four sales persons, Rael, Halima, Moses and Trevor, in four different towns: A, B, C and D.

Sales person A B C D
Rael 10 25 5 4
Halima 12 23 9 2
Moses 14 20 8 1
Trevor 13 20 7 3

The management intends to assign the sales persons to the towns in order to maximize sales. Determine the:

(i) optimal assignment schedule that maximizes weekly sales;

(ii) maximum weekly sales.

Answer

Maximise by converting each entry to an opportunity loss: 25 minus the original entry. Apply the Hungarian method. Reduce each row by its smallest entry, then reduce each column by its smallest entry.

After row reduction:

A B C D
Rael 15 0 20 21
Halima 11 0 14 21
Moses 6 0 12 19
Trevor 7 0 13 17

After column reduction:

A B C D
Rael 9 0 8 4
Halima 5 0 2 4
Moses 0 0 0 2
Trevor 1 0 1 0

Cover zeros with rows Moses and columns B, D. Minimum uncovered entry = 1. Subtract it from uncovered cells and add it at line intersections.

A B C D
Rael 8 0 7 4
Halima 4 0 1 4
Moses 0 1 0 3
Trevor 0 0 0 0

Cover zeros with rows Moses, Trevor and columns B. Minimum uncovered entry = 1. Subtract it from uncovered cells and add it at line intersections.

A B C D
Rael 7 0 6 3
Halima 3 0 0 3
Moses 0 2 0 3
Trevor 0 1 0 0

Choose four independent zeros, with one assignment in every row and column. Read the values from the original table:

Assign To Ksh ‘000
Rael B 25
Halima C 9
Moses A 14
Trevor D 3
Maximum 51

Maximum weekly sales = Ksh. 51,000.

Question 6(b) — 10 marks

Konti Limited intends to invest Ksh 1,500,000 in either project M or project N. The expected net cash inflows from each of the projects is as follows.

Year Project M (Ksh) Project N (Ksh)
1 600,000 550,000
2 1,010,000 970,000
3 710,000 820,000

Additional information: (I) The company’s cost of capital is 14%. (II) Project M is expected to have a salvage value of Ksh 100,000.

(i) For each of the projects, M and N, determine the Net Present Value (NPV).

(ii) Based on the results in (i) above, advise the management on the project to undertake.

Answer

  1. Add M’s Ksh. 100,000 salvage value to its Ksh. 710,000 year-3 inflow. No salvage value is specified for N.
  2. Choose project M: NPV M = Ksh. 350,204.92, versus NPV N = Ksh. 282,316.29. Both are positive, but M creates more value for the same initial outlay.

Project M (including year-3 salvage): discount rate 14%. PV = cash flow ÷ (1 + r)ⁿ. All amounts are Ksh.

Year Net cash flow Discount factor Present value
1 600,000 0.877193 526,315.79
2 1,010,000 0.769468 777,162.20
3 810,000 0.674972 546,726.93
Total PV 1,850,204.92
Initial investment (time 0) -1,500,000
NPV 350,204.92

Project N: discount rate 14%. PV = cash flow ÷ (1 + r)ⁿ. All amounts are Ksh.

Year Net cash flow Discount factor Present value
1 550,000 0.877193 482,456.14
2 970,000 0.769468 746,383.50
3 820,000 0.674972 553,476.64
Total PV 1,782,316.29
Initial investment (time 0) -1,500,000
NPV 282,316.29

Question 7(a) — 10 marks

Kapet Limited intends to launch either product Y or product Z into the market. The following information relates to the net profit and the associated probabilities of the two products under three different market conditions.

Market condition Probability Y (Ksh ‘000) Z (Ksh ‘000)
Boom 0.30 180 280
Neutral 0.45 140 90
Recession 0.25 40 5

(i) For each product, calculate: (I) expected net profit; (II) standard deviation; (III) coefficient of variation.

(ii) Based on the results in (III) above, advise the management on the product to launch.

Answer

  1. Choose product Y on the requested coefficient-of-variation criterion: it has a lower standard deviation per unit of expected profit. Y also has a slightly higher expected profit.

Use μ = Σpx, variance = Σp(x − μ)², standard deviation σ = √variance and CV = σ/μ. Profit and standard deviation below are in Ksh ‘000; variance is in squared thousand-shilling units.

Product Y

State p Profit x x − μ p(x − μ)²
Boom 0.30 180 53 842.70
Neutral 0.45 140 13 76.05
Recession 0.25 40 -87 1,892.25

Product Z

State p Profit x x − μ p(x − μ)²
Boom 0.30 280 154.25 7,137.92
Neutral 0.45 90 -35.75 575.13
Recession 0.25 5 -120.75 3,645.14
Product Expected profit Variance Standard deviation CV ratio CV percentage
Y 127 2,811 53.02 0.417471 41.75%
Z 125.75 11,358.19 106.57 0.847513 84.75%

Question 7(b) — 10 marks

Tamu Butcheries has three butcheries: X, Y and Z. The butcheries have the following quantities of meat available.

Butchery Meat available (kg)
X 160
Y 170
Z 172

Three hotels, Sunlight, Topex and Highland require meat as follows:

Hotel Meat required (kg)
Sunlight 158
Topex 150
Highland 194

The transportation cost, in shillings per kilogram of meat, from each of the butcheries to the hotels is as shown below:

Butchery Sunlight Topex Highland
X 10 7 9
Y 12 10 8
Z 17 12 6.50

Using the North West Corner rule, determine the:

(i) optimal transportation schedule;

(ii) minimum cost of transportation.

Answer

NW allocation steps:

Step Route Selection Quantity
1 X → Sunlight unit cost 10 158
2 X → Topex unit cost 7 2
3 Y → Topex unit cost 10 148
4 Y → Highland unit cost 8 22
5 Z → Highland unit cost 6.50 172

Initial basic feasible schedule:

Source → destination Sunlight Topex Highland Supply
X 158 2 0 160
Y 0 148 22 170
Z 0 0 172 172
Demand 158 150 194 502

Initial transportation cost = Σ(quantity × unit cost) = 4,368 Ksh.

The initial allocation method produces a feasible schedule, but does not by itself prove minimum cost. Apply MODI: uᵢ + vⱼ = cᵢⱼ on basic cells and Δᵢⱼ = cᵢⱼ − uᵢ − vⱼ on nonbasic cells. A negative Δ permits a cost reduction; adjust alternating +/− cells by θ. Zero basic allocations may be used for degeneracy.

Iteration Entering route Δ per unit θ Alternating loop New total cost
1 Y → Sunlight -1 148 +Y→Sunlight; −X→Sunlight; +X→Topex; −Y→Topex 4,220

Optimal schedule:

Source → destination Sunlight Topex Highland Supply
X 10 150 0 160
Y 148 0 22 170
Z 0 0 172 172
Demand 158 150 194 502
Row potentials u X Y Z
Value 0 2 0.50
Column potentials v Sunlight Topex Highland
Value 10 7 6

Final reduced costs (all are nonnegative, proving optimality):

Sunlight Topex Highland
X 0 0 3
Y 0 1 0
Z 6.50 4.50 0

Cost working: 10 × 10 + 150 × 7 + 148 × 12 + 22 × 8 + 172 × 6.50 = 4,220 Ksh.

November 2022

Paper codes: 2903/305; 2906/305; 2907/305; 2926/305; 3103

Question 1(a) — 8 marks

Explain four roles played by a management accountant in a business organization.

Answer

  1. Planning: prepare forecasts, budgets and cost estimates that turn objectives into measurable resource requirements.
  2. Decision support: compare relevant future revenues and costs of alternatives such as making or buying, pricing and investing.
  3. Control: compare actual results with budgets, investigate significant variances and recommend corrective action.
  4. Performance evaluation: report controllable results for responsibility centres so managers can assess efficiency and achievement of targets.

Question 1(b) — 12 marks

The management of Noli Limited intends to launch either product K or product M into the market. The following are the expected net profits or losses and associated probabilities under three market conditions.

Market demand Probability K (Ksh) M (Ksh)
High 0.20 600,000 400,000
Medium 0.50 300,000 500,000
Low 0.30 -100,000 50,000

(i) Draw a decision tree to present the information above.

(ii) Calculate the Expected Monetary Value (EMV) for each of the products, K and M.

(iii) Based on the results in (ii) above, advise the management on the product to launch.

Answer

  1. Launch product M, whose EMV is Ksh. 345,000, compared with Ksh. 240,000 for K. Its expected advantage is Ksh. 105,000 under the supplied probabilities.
Noli: product K or product M
Noli: product K or product M
Alternative Σ probability × payoff Expected gross payoff Option cost Net EMV (Ksh)
Product K 0.2 × (600,000) + 0.5 × (300,000) + 0.3 × (-100,000) 240,000 0 240,000
Product M 0.2 × (400,000) + 0.5 × (500,000) + 0.3 × (50,000) 345,000 0 345,000

Question 2(a) — 8 marks

The following information relates to units produced of a product and the cost of production incurred by Kolo Manufacturers during the first six months of the year 2021.

2021 Units produced Cost of production (Ksh)
January 500 20,000
February 300 18,000
March 700 28,000
April 350 19,000
May 200 15,000
June 600 25,000

(i) Using the high-low method, determine: (I) variable cost per unit; (II) fixed cost for the period. (ii) Formulate the linear cost function in the form of Y = a + bx. (iii) Estimate the production cost if 1,000 units are produced.

Answer

Item Working Result
Highest activity x = 700; cost = 28,000
Lowest activity x = 200; cost = 15,000
Variable cost per unit (28,000 − 15,000) ÷ (700 − 200) 26
Fixed cost 28,000 − 26 × 700 9,800
Cost function Y = a + bx Y = 9,800 + 26x
Cost at 1,000 units 9,800 × 1 + 26 × 1,000 35,800

Select the highest and lowest activity levels, rather than the highest and lowest cost observations.

Question 2(b) — 12 marks

The following information relates to product JZ20 manufactured by Jako Limited:

Item Ksh
Sales (400 units) 1,600,000
Less total costs 1,000,000
Profit 600,000

Fixed costs are 20% of the total costs. (i) Determine: (I) break-even point in units; (II) break-even point in shillings; (III) margin of safety in units; (IV) margin of safety in shillings; (V) contribution-sales ratio. (ii) Calculate the number of units to be manufactured and sold in order to obtain a target profit of Ksh. 124,000.

Answer

Item Working Result
Selling price/unit 1,600,000 ÷ 400 4,000
Fixed costs 20% × 1,000,000 200,000
Variable cost/unit 800,000 ÷ 400 2,000
Contribution/unit 4,000 − 2,000 2,000
Break-even units 200,000 ÷ 2,000 100
Break-even sales 100 × 4,000 400,000
MOS units 400 − 100 300
MOS sales 300 × 4,000 1,200,000
Contribution-sales ratio 2,000 ÷ 4,000 50%
Units for target profit (200,000 + 124,000) ÷ 2,000 162

Question 3(a) — 10 marks

Saleb Limited produces three products: X, Y and Z. The following is the operating statement for the year ended 31 December 2021.

Item (Ksh) Product X Product Y Product Z Total
Sales 100,000 150,000 140,000 390,000
Total sales (as printed) 120,000 90,000 99,000 309,000
Profit / loss -20,000 60,000 41,000 81,000

Additional information: Fixed costs are 1/3 of the total costs. The management is considering dropping product X.

(i) For each product, prepare an operating statement using marginal costing technique.

(ii) Advise the management on whether to drop product X or not.

Answer

  1. The printed row “Total sales” contains the total cost figures; it is treated as total costs, consistent with the stated profits.
  2. Keep product X if its allocated fixed costs continue. X contributes Ksh. 20,000 towards fixed costs; dropping it reduces total profit from Ksh. 81,000 to Ksh. 61,000. Only avoidable fixed costs or a better use of capacity could change that conclusion.
Marginal operating statement (Ksh) X Y Z Total
Sales 100,000 150,000 140,000 390,000
Variable cost: 2/3 of cost 80,000 60,000 66,000 206,000
Contribution 20,000 90,000 74,000 184,000
Fixed cost: 1/3 of cost 40,000 30,000 33,000 103,000
Profit / loss -20,000 60,000 41,000 81,000
Item Working Result
Profit if X is dropped and all fixed costs remain 81,000 − 20,000 61,000

Question 3(b) — 10 marks

Diam Limited intends to invest Ksh. 1,800,000 in either project A or project B. The following are the expected net cash inflows from the projects.

Year A (Ksh) B (Ksh)
1 -200,000 400,000
2 600,000 500,000
3 1,000,000 1,000,000
4 800,000 600,000
5 1,200,000 1,000,000

The cost of capital is 14%.

(i) Calculate the Net Present Value (NPV) for each project.

(ii) Advise the management on the project to invest in.

Answer

  1. Project A NPV = Ksh. 258,120.06; project B NPV = Ksh. 485,199.30. Choose B because it has the higher positive NPV. The negative year-1 cash flow for A is discounted as an outflow, not changed to an inflow.

Project A: discount rate 14%. PV = cash flow ÷ (1 + r)ⁿ. All amounts are Ksh.

Year Net cash flow Discount factor Present value
1 -200,000 0.877193 -175,438.60
2 600,000 0.769468 461,680.52
3 1,000,000 0.674972 674,971.52
4 800,000 0.592080 473,664.22
5 1,200,000 0.519369 623,242.40
Total PV 2,058,120.06
Initial investment (time 0) -1,800,000
NPV 258,120.06

Project B: discount rate 14%. PV = cash flow ÷ (1 + r)ⁿ. All amounts are Ksh.

Year Net cash flow Discount factor Present value
1 400,000 0.877193 350,877.19
2 500,000 0.769468 384,733.76
3 1,000,000 0.674972 674,971.52
4 600,000 0.592080 355,248.17
5 1,000,000 0.519369 519,368.66
Total PV 2,285,199.30
Initial investment (time 0) -1,800,000
NPV 485,199.30

Question 4(a) — 8 marks

Mobex Limited operates two divisions, P and Q. Both divisions have proposed similar investment projects worth Ksh. 20,000,000 each. Out of this investment, the controllable contribution is 14% of the proposed investment for division P, while division Q has estimated their controllable contribution to be 18%. The capital charge is 16% of the proposed investment for each division. Using the residual income approach, advise the management on the division whose project should be undertaken.

Answer

  1. Undertake division Q’s project: it earns Ksh. 400,000 above the capital charge. P’s project falls short by Ksh. 400,000.
Division Controllable contribution (Ksh) Capital charge (Ksh) Residual income (Ksh)
P 20,000,000 × 14% = 2,800,000 3,200,000 -400,000
Q 20,000,000 × 18% = 3,600,000 3,200,000 400,000

Question 4(b) — 12 marks

Saba Limited has four salespersons: Abdi, Moses, Lilian and Mary. Each salesperson is to be assigned to a single town. The following table shows the weekly sales in thousands of shillings, made by each salesperson in each of the towns.

Town Abdi Moses Lilian Mary
A 20 16 13 18
B 10 14 16 13
C 14 6 10 18
D 16 12 8 15

Assign each salesperson to each town in order to maximize the total sales.

Answer

Maximise by converting each entry to an opportunity loss: 20 minus the original entry. Apply the Hungarian method. Reduce each row by its smallest entry, then reduce each column by its smallest entry.

After row reduction:

Abdi Moses Lilian Mary
A 0 4 7 2
B 6 2 0 3
C 4 12 8 0
D 0 4 8 1

After column reduction:

Abdi Moses Lilian Mary
A 0 2 7 2
B 6 0 0 3
C 4 10 8 0
D 0 2 8 1

Cover zeros with rows B and columns Abdi, Mary. Minimum uncovered entry = 2. Subtract it from uncovered cells and add it at line intersections.

Abdi Moses Lilian Mary
A 0 0 5 2
B 8 0 0 5
C 4 8 6 0
D 0 0 6 1

Choose four independent zeros, with one assignment in every row and column. Read the values from the original table:

Assign To Ksh ‘000
A Abdi 20
B Lilian 16
C Mary 18
D Moses 12
Maximum 66

Maximum weekly sales = Ksh. 66,000.

Question 5(a) — 8 marks

A teller at Kiti savings and credit society can serve an average of one customer in every 3 minutes. On average, a customer arrives after every 4 minutes.

Using the simple queuing model, determine the:

(i) average number of customers in the queue;

(ii) average number of customers in the queuing system;

(iii) average time a customer spends in the system.

Answer

λ = 60/4 = 15 per hour; μ = 60/3 = 20 per hour.

Use the stable M/M/1 model: one server, Poisson arrivals, independent exponential service times and λ < μ. Service completions are counted per time interval; service durations are exponential.

Item Working Result
Arrival rate λ Convert arrivals to an hourly rate 15 per hour
Service rate μ Convert services to an hourly rate 20 per hour
Busy proportion ρ λ / μ 0.7500 = 75.00%
Idle proportion P₀ 1 − ρ 0.2500 = 25.00%
Mean queue length Lq λ² / [μ(μ − λ)] 2.25
Mean number in system L λ / (μ − λ) 3
Mean time in system W 1 / (μ − λ) 0.200000 hour = 12 minutes
Mean waiting time Wq λ / [μ(μ − λ)] 0.150000 hour = 9 minutes = 540 seconds

Question 5(b) — 12 marks

Ziwa Dairy Limited has three milk processing plants; A, B and C. The company supplies milk to four different towns; W, X, Y and Z. The daily quantity of milk available from the plants is as follows.

Plant Litres available
A 5,000
B 8,000
C 7,000

The daily quantity of milk required in each of the towns is as shown below.

Town Litres required
W 4,000
X 6,000
Y 7,000
Z 5,000

The cost of transporting one litre of milk from each plant to each of the towns, in Kenya shillings, is as shown below.

Plant W X Y Z
A 2 5 4 3
B 4 1 5 4
C 3 2 2 3

Using the North-West corner rule, determine the:

(i) optimal transportation schedule that will minimize transportation cost;

(ii) minimum transportation cost.

Answer

Demand exceeds available supply by 2,000. Add a dummy source of 2,000 at zero accounting transport cost to balance the tableau. Dummy allocations represent unmet demand, not actual deliveries; real shortage penalties are not supplied.

NW allocation steps:

Step Route Selection Quantity
1 A → W unit cost 2 4,000
2 A → X unit cost 5 1,000
3 B → X unit cost 1 5,000
4 B → Y unit cost 5 3,000
5 C → Y unit cost 2 4,000
6 C → Z unit cost 3 3,000
7 Dummy (unmet demand) → Z unit cost 0 2,000

Initial basic feasible schedule:

Source → destination W X Y Z Supply
A 4,000 1,000 0 0 5,000
B 0 5,000 3,000 0 8,000
C 0 0 4,000 3,000 7,000
Dummy (unmet demand) 0 0 0 2,000 2,000
Demand 4,000 6,000 7,000 5,000 22,000

Initial transportation cost = Σ(quantity × unit cost) = 50,000 Ksh.

The initial allocation method produces a feasible schedule, but does not by itself prove minimum cost. Apply MODI: uᵢ + vⱼ = cᵢⱼ on basic cells and Δᵢⱼ = cᵢⱼ − uᵢ − vⱼ on nonbasic cells. A negative Δ permits a cost reduction; adjust alternating +/− cells by θ. Zero basic allocations may be used for degeneracy.

Iteration Entering route Δ per unit θ Alternating loop New total cost
1 A → Y -5 1,000 +A→Y; −B→Y; +B→X; −A→X 45,000
2 A → Z -2 1,000 +A→Z; −C→Z; +C→Y; −A→Y 43,000
3 B → W -1 2,000 +B→W; −A→W; +A→Z; −C→Z; +C→Y; −B→Y 41,000
4 B → Z -1 2,000 +B→Z; −A→Z; +A→W; −B→W 39,000

Optimal schedule:

Source → destination W X Y Z Supply
A 4,000 0 0 1,000 5,000
B 0 6,000 0 2,000 8,000
C 0 0 7,000 0 7,000
Dummy (unmet demand) 0 0 0 2,000 2,000
Demand 4,000 6,000 7,000 5,000 22,000
Row potentials u A B C Dummy (unmet demand)
Value 0 1 0 -3
Column potentials v W X Y Z
Value 2 0 2 3

Final reduced costs (all are nonnegative, proving optimality):

W X Y Z
A 0 5 2 0
B 1 0 2 0
C 1 2 0 0
Dummy (unmet demand) 1 3 1 0

Cost working: 4,000 × 2 + 1,000 × 3 + 6,000 × 1 + 2,000 × 4 + 7,000 × 2 + 2,000 × 0 = 39,000 Ksh.

Question 6(a) — 8 marks

Explain each of the following terms as used in queuing.

(i) Queue discipline;

(ii) Queuing system;

(iii) Multi-channel service facility;

(iv) Waiting time.

Answer

  1. Queue discipline: the rule deciding which waiting customer receives service next, such as first-come, first-served or priority order.
  2. Queuing system: the complete arrangement of the calling population, arrival process, waiting space, service channels and service process.
  3. Multi-channel service facility: two or more parallel servers can serve customers at the same service stage, for example several bank tellers.
  4. Waiting time: time spent in the queue before service begins; distinguish it from time in the system, which also includes service time.

Question 6(b) — 12 marks

Mangy Limited manufactures two products, Wye and Zed, using two types of materials: M1 and M2.

The following estimates relate to the month of January 2023. Expected sales of product Wye and Zed are 10,000 units and 8,400 units respectively. Selling prices per unit are Ksh. 800 and Ksh. 500 respectively.

Material kg per unit Wye Zed
M1 5 1
M2 2 3

Material cost per kilogram: M1 Ksh. 60; M2 Ksh. 100.

Finished goods inventory Wye Zed
1 January 280 360
31 January 320 340
Raw material inventory (kg) M1 M2
1 January 70 100
31 January 360 300

Prepare:

(i) sales budget in shillings;

(ii) production budget in units;

(iii) material usage budget in units;

(iv) material purchases budget in shillings.

Answer

Sales budget:

Product Sales units Price (Ksh) Sales value (Ksh)
Wye 10,000 800 8,000,000
Zed 8,400 500 4,200,000
Total 12,200,000

Production = sales + closing finished goods − opening finished goods:

Product Sales Add closing Less opening Produce units
Wye 10,000 320 280 10,040
Zed 8,400 340 360 8,380

Material usage budget (kg):

Material Wye Zed Total kg
M1 50,200 8,380 58,580
M2 20,080 25,140 45,220

Purchases = usage + closing raw material − opening raw material:

Material Usage kg Add closing kg Less opening kg Purchase kg Cost/kg (Ksh) Purchases (Ksh)
M1 58,580 360 70 58,870 60 3,532,200
M2 45,220 300 100 45,420 100 4,542,000
Total 8,074,200

Question 7(a) — 10 marks

Explain five advantages of decentralization in the management of a business organisation.

Answer

  1. Quicker decisions: local managers can respond to customer and operating issues without waiting for head-office approval.
  2. Better local information: decisions reflect detailed knowledge of regional markets, staff and production conditions.
  3. Manager development: delegated authority gives managers experience in planning, decision-making and accountability.
  4. Motivation: meaningful authority and responsibility can increase initiative and ownership of results.
  5. Senior management focus: routine decisions move to divisions, leaving top management more time for strategy and organisation-wide coordination.

Question 7(b) — 10 marks

The following information relates to the cost of production incurred by Aleem Limited for the year 2021.

Units produced Cost of production (Ksh ‘000)
10 8
12 10
14 10
15 14
16 15
20 18

(i) Formulate a linear regression equation in the form: Y = a + bx.

(ii) Estimate the cost of producing 30 units of the product.

Answer

Units produced x Cost y (Ksh ‘000) x² xy
10 8 100 80
12 10 144 120
14 10 196 140
15 14 225 210
16 15 256 240
20 18 400 360
Σ 75 1,321 1,150
Item Working Result
Totals n=6; Σx=87; Σy=75
Slope b [6 × 1,150 − 87 × 75] ÷ [6 × 1,321 − 87²] 1.050420
Intercept a [75 − (1.050420 × 87)] ÷ 6 -2.731092
Regression equation ŷ = a + bx ŷ = -2.731092 + (1.050420)x
Prediction at x=30 -2.731092 + (1.050420 × 30) 28.78

The predicted cost in shillings is 28,781.51; the regression table and equation use Ksh ‘000.