When the Price of a Flashlight Is $5,the Number of Flashlights

Essay

When the price of a flashlight is $5,the number of flashlights demanded is 600 units.When the price increases to $20 per unit,the quantity demanded falls to 200 units.Moreover,if the price of the cells used to operate these flashlights falls by 200 percent,the demand for flashlights increases from 200 units to 300 units.
a)Calculate the arc price elasticity of demand.
b)Calculate the cross-price elasticity of demand.
c)When Joe earns $30,he purchases 20 flashlights.When his income increases to $120,his quantity demanded increases to 60 units.Calculate Joe's income elasticity of demand for flashlights.