Answer
Cross elasticity of demand is -1.5, they are close complements.
Cross elasticity of demand is different at different prices.
Work Step by Step
Formula of cross elasticity of demand:
Percentage change in quantity demanded of good A/percentage change in price of good b
Taking movies to be good a and golf to be good b,
When price of golf is 50 dollars,
$\frac{15-10}{15}$ ÷ $\frac{9-11}{11}$ = -1.5
When price of golf is 35 dollars,
$\frac{25-15}{25}$ ÷ $\frac{9-11}{11}$ = -1.8
When price of golf is 20 dollars,
$\frac{40-20}{40}$ ÷ $\frac{9-11}{11}$ = -4.5
Golf and movies are close complements due to the negative value of cross elasticity of demand. This would mean that an increase in price of movies, which implies a decrease in the quantity demanded of movies, would result in a decrease in quantity demanded of golf, and thus these goods are complements.
