# A student has earned the following scores on four 100-point math tests: 66, 70, 85, 88. What score must the student earn on the fifth to earn an average grade of 80 for those five tests?

##### 1 Answer

Jun 20, 2017

91

#### Explanation:

When we take an average, we sum the values and then divide by the count (the number of values).

In this case, we can write the scores of the tests and the desired average this way: