A ratio is a comparison between two numbers, expressed as a division problem. For example, x is to y is written as x/y, and this ratio relationships can be stated in one of several ways, including:
- x to y
- That ratio of x to y
- x is to y
- x:y
Ratio problems will most often appear in word problems where you have to find a relationship and use the relationship to arrive at the answer. For example:
If the ratio of the cost of apples to pears is 30 to 22, and the cost of an apple is $0.50, then what is the cost of a pear?
Here's how to solve this problem:
| Step 0: |
Original Problem |
Ratio of cost of apples to pears is 30 to 22, and cost of apple is $0.50 |
| Step 1: |
From the problem, we know that 30 apples cost as much as 22 pears, so first multiply the number of apples by the cost of each apple to get the total cost of 30 apples. |
(30)($0.50) = $15.00 |
| Step 2: |
Thus 22 pears cost $15.00, so divide $15.00 by 22 to get the cost of each pear. |
15/22 = $0.68 |