Answer:
By the midpoint formula, his income elasticity of demand for pro football game tickets is equal to +3, and football game tickets are normal goods.
Step-by-step explanation:
The formula for calculating income elasticity of demand using the midpoint method is:
income elasticity of demand = {change in quantity demanded / [(old quantity + new quantity) / 2]} / {change in income / [(old income + new income) / 2]}
= {2 / [(2 + 4) / 2]} / {10,000 / [(40,000 + 50,000) / 2]} = (2 / 3) / (10,000 / 45,000) = 0.67 / 0.222 = 3
when the income elasticity of demand is higher than 1, the goods are normal goods.