Rates

What is a rate: A ratio of two measurements having different unit. An example would be a bag of chips costs $3.19. It has 14.5 oz. What is the cost for one ounce. The two measurements are money and ounces. So, this is a rate. To solve it we place the unit we want to get to one on as the denominator. The other unit is the numerator. In this case we want to know the cost of one ounce so 14.5 is the denominator and $3.19 is the numerator. To solve divide both by 14.5 to find the rate.

Practice Sites:

IXL - Limited Practice time. Solve the rates.

Solve the Rates - Find the missing value.

AAA Math - More Practice Solving Rates

Math Games site - Expressing rates

Math Games site - Expressing unit rates

Another example, let's say someone drives 146 miles in two hours. They want to know how many miles they drive in one hour. To solve this we set up a rate. Since it is hours we want to get to one, that number will go on the bottom (denominator) and the miles will go on the top (numerator). So put 146 miles over 2 hours. 146 miles/2 hours. Now we want hours to be one, so we have to divide by the number of hours there, in this case 2. Whatever we do to the bottom we do to the top. 146 ÷ 2 / 2 ÷ 2. So we have 78 miles/ 1 hour. This means the person drives 78 miles in one hour.

In this example we want to know What is the average rainfall for one day if in 28 days we had 7 inches of rain.