A consumer buys 10 units of a good at a price of Rs 6 per unit

A consumer buys 10 units of a good at a price of Rs 6 per unit. Price Elasticity of Demand is (-) 1. At what price will he buy 12 units.Use expenditure approach of Price Elasticity of Demand to answer this question.

Given, {{E}_{d}} = (-) 1
In this case, when Elasticity of Demand is (-)1, total expenditure will remain constant.
Total expenditure = 10 x 6 = Rs 60 Total expenditure does not change.
When quantity is 12 units,
Price = TE/Q = 60/12 = rs 5 per unit