Problem: Tim Horton decided to increase its total revenue by choosing a strategy of decreasing the price of coffee from $3:00 per cup to $2.5 per cup. When the price was $3:00, the total amount of coffee cups sold was 50000/= per week. However, when the price decreased to $2.50 per cup, the total amount of cup sold increased to 70000/= per week. Calculate price elasticity of demand and explain how this will affect the revenue of Tim Horton.