Loading....

WAEC SSCE - Economics - 2005 (Essay)

Question 1 Report


The diagram above illustrates the demand for and supply of maize. Use the information in the diagram to answer the questions that follow 

(a) (i) What is the total revenue of the farmer at the initial equilibrium? 
(ii) Calculate the total revenue of the farmer if the supply curve shifts to S\(_1\)S\(_1\)
(b) What change occurs in the total revenue of the farmer when the price falls from 100 Dollars to 40 Dollars per tonne? 
(b) (i)Use the figures in the diagram to determine the price elasticity of demand for maize (u) Interprete your answer. 
(c) Give two reasons for the shift of the supply curve from SS to S\(_1\)S\(_1\)

Answer Details

From the diagram, the demand curve DD cuts the original supply curve SS at the initial equilibrium of quantity \(30\) tonnes and price \(\$100\) per tonne. When supply shifts to \(S_1S_1\), the new equilibrium is at quantity \(40\) tonnes and price \(\$40\) per tonne. All working below uses these read-off values.

(a)(i) Total revenue at the initial equilibrium

Total revenue is price multiplied by quantity sold, \(TR = P \times Q\).

\[TR = \$100 \times 30 = \$3{,}000\]

The farmer earns \(\$3{,}000\) at the initial equilibrium.

(a)(ii) Total revenue after supply shifts to \(S_1S_1\)

\[TR_1 = \$40 \times 40 = \$1{,}600\]

After the shift the farmer earns \(\$1{,}600\).

(b) Change in total revenue when price falls from \(\$100\) to \(\$40\) per tonne

\[\Delta TR = TR_1 - TR = \$1{,}600 - \$3{,}000 = -\$1{,}400\]

Total revenue falls by \(\$1{,}400\). Notice that although more maize is now sold (\(40\) tonnes instead of \(30\)), revenue still drops. This happens because the price cut of \(60\%\) is far larger in proportion than the rise in quantity, which is the tell-tale sign of an inelastic demand, confirmed below.

(c)(i) Price elasticity of demand for maize

Elasticity is measured along the demand curve DD, using the two price-quantity points it passes through: \((P=100,\ Q=30)\) and \((P=40,\ Q=40)\). Taking the first point as the base:

\[E_d = \frac{\%\ \text{change in quantity demanded}}{\%\ \text{change in price}} = \frac{\Delta Q / Q_1}{\Delta P / P_1}\]\[\Delta Q = 40 - 30 = 10, \qquad \Delta P = 40 - 100 = -60\]\[E_d = \frac{10/30}{-60/100} = \frac{0.3333}{-0.6} = -0.56\]

Ignoring the negative sign (which merely reflects the downward-sloping demand curve), \(|E_d| \approx \mathbf{0.56}\).

(c)(ii) Interpretation

Since \(|E_d| = 0.56 < 1\), the demand for maize is price inelastic. A \(1\%\) change in price brings about only about a \(0.56\%\) change in quantity demanded, so buyers are not very responsive to price changes. This is typical of a food staple like maize, and it explains the paradox in part (b): cutting the price shrinks the farmer's total revenue rather than raising it.

(d) Two reasons for the shift of supply from SS to \(S_1S_1\)

The curve shifts outward to the right, meaning more is supplied, so the causes are factors that make production easier or cheaper:

  1. Favourable weather / good rainfall during the growing season, giving a larger harvest at every price.
  2. A fall in the cost of production (for example cheaper fertiliser, seeds or fuel) or a government subsidy to maize farmers, both of which raise the quantity farmers are willing to supply. Improved technology or high-yield seed varieties would have the same effect.
1
2
3
4
5
6
7
8
9
10
11
12