# Jameson received four grades on his algebra tests, bringing his average to an 88 for that class. What grade would he have to have on his last test in order to bring his average up to 90?

##### 2 Answers

Jameson needs to make

#### Explanation:

Let's let each of the test grades be represented by

The average of the first four tests is

Jameson would like the final average of the five tests to be

We notice that this average contains the sum of

We can now substitute this into the average of the five tests

Solving for

So Jameson needs to make

Jameson needs 98 on the next test.

#### Explanation:

From this we can can see that

The mean of 4 tests is

If the mean of 5 tests is

The difference between the two totals is how much Jameson needs to score on the next test to average 90.