A piueria lowers the price of its most popular takeaway pizza, the Margherita, from $5 to $4.50 and finds that the weekly quantity demanded of the pizzas goes up from 60 per week to 72. 

1. Calculate the percentage changes in price and quantity demanded. 

2. Calculate the price elasticity of demand for the pizzas. 

3. Calculate the change in total revenue that the pizzeria will experience following the fall in price. 

4. Draw a "revenue box" diagram to illustrate the effect on quantity demanded and total revenue following the price change for the Margherita. 

5. Was the firm sensible to lower the price of the Margherita? Explain your answe,