4-5
21. Suppose price decreases from $27.00 to $13.00. Using the mid-point formula, the percentage change
in price is:
22. Suppose when the price of calculators is $18, the quantity demanded is 90, and when the price is
$22, the quantity demanded drops to 70. Using the mid-point method, the price elasticity of demand is:
23. Suppose when the price of movie tickets is $7.50, the quantity demanded is 550, and when the price
is $8.50, the quantity demanded is 450. Using the mid-point method, the price elasticity of demand is:
24. Suppose when the price of a can of tuna is $1.30, the quantity demanded is 9, and when the price is
$1.50, the quantity demanded is 7. Using the mid-point method, the price elasticity of demand is:
25. Suppose when the price of mascara is $12, the quantity demanded is 450, and when the price is $8,
the quantity demanded is 550. Using the mid-point method, the price elasticity of demand is: