Practice!

Sample Problem

The following shows the price of bowls at three stores.

Store A: 15 dollars for 5 bowls

Store B: 8 dollars for 3 bowls

Store C: 30 dollars for 10 bowls

If Tina wants to buy 30 bowls, at which store it will be cheapest?

Solution

Find the ratio of bowls to cost for each store:

Store A is 5:15

Store B is 3:8

Store C is 10:30

Then, multiply each part of the ratios with a common factor to make the number of bowls as 30.

Store A, 5:15= (5× 6) : (15× 6) = 30:90

Store B, 3:8= (3× 10) : (8× 10) = 30:80

Store C, 10:30 = (10× 3) : (30 × 3) = 30:90

Then, compare the cost for each store; we can find that store B is at the lowest cost.