In: Economics
Suppose that the current market price for DVRs is $200 (P1) and average consumer income (Y1) is $50,000. Under these conditions, 7.5 million DVRs will be sold this year (Q1). Econometricians have estimated that the elasticity of demand for DVRs is -2.65 and the income elasticity for DVRs is 3.5. Use this information to predict the annual number of DVRs (Q2) sold under the following conditions:
(a) Using midpoint method,
Elasticity of demand = (Change in quantity / Average quantity) / (Change in Price / Average price)
-2.65 = [(Q2 - 7.5) / (Q2 + 7.5)] / [(185 - 200) / (185 + 200)]
-2.65 = [(Q2 - 7.5) / (Q2 + 7.5)] / (-15 / 385)
2.65 = [385 x (Q2 - 7.5)] / [15 x (Q2 + 7.5)]
2.65 = (385Q2 - 2887.5) / (15Q2 + 112.5)
39.75Q2 + 298.125 = 385Q2 - 2887.5
345.25Q2 = 3185.625
Q2 = 9.23 million
(b) Using midpoint method,
Income Elasticity of demand = (Change in quantity / Average quantity) / (Change in income / Average income)
3.5 = [(Q2 - 7.5) / (Q2 + 7.5)] / [(52,000 - 50,000) / (52,000 + 50,000)]
3.5 = [(Q2 - 7.5) / (Q2 + 7.5)] / (2,000 / 102,000)
3.5 = [(Q2 - 7.5) / (Q2 + 7.5)] / (1 / 51)
3.5 = [51 x (Q2 - 7.5)] / [(Q2 + 7.5)]
3.5Q2 + 26.25 = 51Q2 - 382.5
47.5Q2 = 408.75
Q2 = 8.61 million
(c)
For case (a), increase in demand = (9.23 - 7.5) million = 1.73 million
For case (b), increase in demand = (8.61 - 7.5) million = 1.11 million
Overall increase in demand = (1.73 + 1.11) million = 2.84 million
New value of demand = (7 + 2.84) million = 9.84 million