Question 1 OR (b)

Three departments: equilibrium prices, value added and feasibility of a new output plan

12 marks

Time to write
About 24 minutes
Topic
Leontief input-output model

Question

Question 1 OR (b) · 12 marks

A manufacturing unit has three departments that produce output for inter-departmental consumption and for final consumers. The inter-departmental flow of the products of its three departments is as follows:

ProducerInter-Department Consumption (tons)Final Demand (tons)
Department XDepartment YDepartment Z
Department X12060060
Department Y0305050
Department Z50809070

Labour required by departments X, Y and Z is 70, 0 and 150 labour days respectively and the wage rate is ₹350 per labour day.

Using matrices, you are required to:

  1. Compute the equilibrium prices for the three departments from the above table.

  2. Compute the total value added.

  3. If the domestic demand changes by 60, 0 and 30 tons respectively for departments X, Y and Z, what change in the gross output of each department is needed to meet the demand?

  4. If 200 labour days are available in all, is the new gross output feasible?

  5. Find the change in the total value added.

Reworded from the university paper: names and figures differ, the task is the same. The original paper belongs to the University of Delhi. See DU's question bank.

Before you write

Read off the question and its marks

24 minfor 12 marks

Read from the question

  • Compute…What…?Are…?5 questions in all: answer every one.
  • ComputeFormula first, then the working, then the answer with its unit (₹, %, units).

Write it in this order

  1. Read the data; note exactly what is asked 2 min
  2. 1 Technology matrix and (I − A)⁻¹ 3 marks 5 min
  3. 2 Equilibrium prices 3 marks 5 min
  4. 3 Total value added 1 mark 2 min
  5. 4 Change in gross output 2 marks 3 min
  6. 5 Labour feasibility 2 marks 3 min
  7. 6 Change in value added 1 mark 2 min
  8. Check: arithmetic, units (₹, %), final answer underlined 2 min

Try it first. About 24 minutes for 12 marks. Write it out, then open the solution.

Solution

Hover or tap a marked figure, like 72,000, to see how it is made and where else it appears.

This is a Leontief open model with three producing departments and labour as the only primary input.

Gross outputs and technology matrix. Gross output of a department = its inter-departmental sales + final demand: X = 120 + 60 + 0 + 60 = 240 (X), 0 + 30 + 50 + 50 = 130 (Y), 50 + 80 + 90 + 70 = 290 (Z).

ProducerDept XDept YDept ZFinal demandGross output
Department X12060060240
Department Y0305050130
Department Z50809070290
Labour (days)700150

Dividing each column by the gross output of the using department gives aᵢⱼ = xᵢⱼ / Xⱼ:

A = [[120/240, 60/130, 0/290], [0/240, 30/130, 50/290], [50/240, 80/130, 90/290]] = [[1/2, 6/13, 0], [0, 3/13, 5/29], [5/24, 8/13, 9/29]]

Labour per unit of output: l = [70/240, 0/130, 150/290] = [7/24, 0, 15/29] labour days.

I − A = [[1/2, −6/13, 0], [0, 10/13, −5/29], [−5/24, −8/13, 20/29]], with |I − A| = 295/1508 ≈ 0.1956 > 0 and leading minors 1/2 and 5/13 positive, so the system is viable (Hawkins-Simon).

(I − A)⁻¹ = (adj (I − A)) / |I − A| = [[128/59, 96/59, 24/59], [65/354, 104/59, 26/59], [145/177, 609/295, 116/59]] ≈ [[2.1695, 1.6271, 0.4068], [0.1836, 1.7627, 0.4407], [0.8192, 2.0644, 1.9661]].

(i) Equilibrium prices

Value added per ton is the wage cost per ton: v = 350 × l = [350 × 7/24, 0, 350 × 15/29] = [102.0833, 0, 181.0345]. Prices satisfy (I − A)ᵀP = v:

(1/2)P₁ − (5/24)P₃ = 102.0833 −(6/13)P₁ + (10/13)P₂ − (8/13)P₃ = 0 −(5/29)P₂ + (20/29)P₃ = 181.0345

Solving, P = [(I − A)ᵀ]⁻¹v:

P₁ = ₹369.77, P₂ = ₹539.83, P₃ = ₹397.46 per ton.

Check (column X): 0.5 × 369.77 − (5/24) × 397.46 = 184.89 − 82.80 = 102.08 ✓.

(ii) Total value added

Value added is the wage bill: 350 × (70 + 0 + 150) = ₹77,000. Check: value of final demand at equilibrium prices = 60 × 369.77 + 50 × 539.83 + 70 × 397.46 = ₹77,000 (exactly, before rounding).

(iii) Change in gross output for the change in demand ΔD = [60, 0, 30]ᵀ

ΔX = (I − A)⁻¹ ΔD:

ΔX₁ = (128 × 60 + 24 × 30)/59 = 8400/59 = 142.37 tons ΔX₂ = (65/354) × 60 + (26/59) × 30 = 1430/59 = 24.24 tons ΔX₃ = (145/177) × 60 + (116/59) × 30 = 6380/59 = 108.14 tons

DepartmentPresent gross outputChangeNew gross output
X240.00142.37382.37
Y130.0024.24154.24
Z290.00108.14398.14

(iv) Is the new gross output feasible with 200 labour days?

Labour needed = (7/24)(382.37) + 0 × (154.24) + (15/29)(398.14) = 111.53 + 0 + 205.93 = 317.46 labour days. Only 200 labour days are available, so the new gross output is not feasible (short by 117.46 days). (Even the present output needs 220 days.)

(v) Change in total value added

ΔVA = 350 × (labour for ΔX) = 350 × [(7/24)(142.37) + (15/29)(108.14)] = 350 × 97.46 = ₹34,110.17 (equivalently, ΔD valued at equilibrium prices: 60 × 369.77 + 30 × 397.46 = ₹34,110.17).

Where the 12 marks sit

#ComponentMarks
1Technology matrix and (I − A)⁻¹3
2Equilibrium prices3
3Total value added1
4Change in gross output2
5Labour feasibility2
6Change in value added1
Total12
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