Question

Denise has taken four math tests this semester and

has received grades of 89, 85, 96 and 87. What is the
minimum score that Denise needs to receive on the
next test in order to get an average math grade of at
least 90?

Answer 1

93

Explanation:

Setup an equation. Add the 5 tests together, the unknown test will be represented by x, Since there are 5 tests total, you will divide by 5. to find the average.

`(89 + 85+96+87+x)/(5) = 90`

To solve first multiply both side by 5.

`(5) (89 + 85+96+87+x)/(5) = 90 (5)`

`89 + 85+96+87+x = 450`

Add the left side and then solve for x

`357 + x = 450`

Subtract 357 from both sides

357 - 357 + x = 450 - 357

x = 93

The last test has to be a score of 93 to get an average of 90.