# P7

QUESTION: In one week, a bookstore sold 1,260 books. The pie chart shows information about the 3 different types of books sold. The angle for the paperback portion is $224\degree$. The ratio of hardbacks to audiobooks is 3:1. Work out the number of audiobooks sold by this bookstore in one week.

ANSWER: We know that the formula for finding the angle is

$\text{angle }=\dfrac{\text{number in one category}}{\text{sum of all categories}}\times 360$

This time we know the angle (224), and the sum of all categories (1,260). So, the equation becomes

$224\degree =\dfrac{\text{paperbacks sold}}{1,260}\times360$

Divide by 360 and then multiply by 1,260 to get

$\text{paperbacks sold}=\dfrac{224}{360}\times1,260=784$

The number of paperbacks sold is 784, so the number of other books sold is $1,260-784=476$. The ratio of hardbacks:audiobooks is 3:1, so audiobooks constitute 1 part out of 4 in the ratio. Therefore, we get

$\text{audiobooks sold }=\dfrac{476}{4}=119$