Answer: (1) 700 pizzas
(2) Its revenue increases by $2600.
Explanation:
Given that,
price elasticity of demand for his pizza = -4
Percentage change in price = 10%
Initial Quantity,[tex]Q_{0}[/tex] = 500 Pizzas
Elasticity of demand = [tex]\frac{Percentage\ change\ in\ quantity }{Percentage\ change\ in\ price }[/tex]
-4 = [tex]\frac{Percentage\ change\ in\ quantity }{0.1 }[/tex]
[tex]\frac{Percentage\ change\ in\ quantity }[/tex] = -4 × 0.1
[tex]\frac{Q_{1}-Q_{0}}{Q_{0}}[/tex] = 0.4
[tex]\frac{Q_{1}-500}{500}[/tex] = 0.4
∴ [tex]Q_{1}[/tex] = 700
Initial price, [tex]P_{0}[/tex] = $20
Changed price, [tex]P_{1}[/tex] = $18
Revenue at t = 0
[tex]P_{0} Q_{0}[/tex] = 500 × 20 =$10000
Revenue at t = 1
[tex]P_{1} Q_{1}[/tex] = 700 × 18 = $12600
Therefore, from the above calculations it was seen that his revenue increases by ($12600 - $10000)= $2600 and its sales increases to 700.