A firm producing decorative candles lowers the price of one of its scented candles from $4 to $3.60 and finds that the weekly quantity demanded of the candles goes up from 600 per week to 630. 

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

2. Calculate the price elasticity of demand for the scented candles. 

3. Calculate the change in total revenue that the firm 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 scented candle. 

5. Was the firm sensible to lower the price of the scented candles? Explain your answer