# 1.8 — Price Elasticity — Practice Problems

The demand for monthly cell phone plans is given by:

\[q_D = 50-0.5p\]

## Question 1

Write the *inverse* demand function.

## Question 2

Calculate the price elasticity of demand when the price is $10. Is this relatively elastic or inelastic?

## Question 3

Calculate the price elasticity of demand when the price is $70. Is this relatively elastic or inelastic?

## Question 4

At what price is demand unit elastic \((\epsilon=-1)\)?

## Question 5

Calculate the total revenue at $10.

## Question 6

Calculate the total revenue at $70.

## Question 7

Calculate the total revenue at the price you found for question 4.