# A consumer spends Rs 100 on a good priced at Rs 4 per unit. When its price falls by 25 percent, the consumer spends Rs 75 on the good. Calculate the price elasticity of demand by the Percentage method. - Economics

A consumer spends Rs 100 on a good priced at Rs 4 per unit. When its price falls by 25 percent, the consumer spends Rs 75 on the good. Calculate the price elasticity of demand by the  Percentage method.

#### Solution

Given:

Actual Total Expenditure (TE0) Rs 100

Change in Total Expenditure (TE1) Rs 75

Actual Price (P0) Rs 4

Percentage change in price - -25

Percentage change in price = (P_1 - P_0)/P_0 xx 100

= -25 = (P_1 - 4)/4 xx 100

(-100)/100 = P_1 - 4

P_1 = 3

Therefore,

 Price(P) Total Expenditure (TE) = Price (P) × Quantity (Q Quantity (Q) = "TE"/P P0 = Rs = 4 TE0 = Rs 100 Q0 = 2 P1 = Rs 3 TE1 = Rs 75 Q1= 25

Ed = (-) "Percentage change in quantity demanded"/"Percentage change in price"

Ed = (-)  ("Changeindemand"/"Actualdemand"xx100)/-25

Ed = (-) ((Q_1 - Q_0)/Q_0 xx 100)/-25

Ed = (-) ((25 - 25)/25 xx 100)/-25

Ed = (-) (-20)/25

∴ Ed = 0

Thus, the price elasticity of demand is 0.

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