The 10″ pizza sells for $3.99 at my favourite pizza store. The store claims they have a great deal on the large 12″ pizza, which is specially priced at $ 4.31. What is the per cent discount the store is offering?
Answer
25
The small pizza has a diameter of 10″ and therefore, an area proportional to 10^2 = 100.
The large pizza has a diameter of 12″ and, therefore, an area proportional to 12^2 = 144.
If the pizzas are priced according to their areas, then,
price of large pizza / price of small
pizza = (12 / 10)^2 = 1.44
Normal price of large pizza = 1.44 x $3.99 = $5.75.
Thus, discount on large pizza = [1 – ($4.31 / $5.75)] x 100 = 25%.
