Question

For each of the following cases, calculate the arc price elasticity of demand and state Wethersfield demand is elastic, inelastic or unit elastic
a) When the price of milk increases for $2.25 to $2.50 per gallon, the quantity demand falls from 100 gallons 5o 90 gallons
b) When the price of paperback books falls from $7.00- $6.50 the quantity demand rises from 100 to 150
c) When the rent on apartments rises from $500 to $550, the quantity demanded decreases from 1,000 to 950