Question

On his first biology test, Bob received the following scores: 72, 86, 92, 63, and 77. What test score must Bob earn on his sixth test so that his average (mean score) for all six tests will be 80?

Answer 1

90

Explanation:

Create an equation where all the numbers are added together and divided by 6 to equal 80:

`(72+86+92+63+77+x)/(6) = 80`

Simplify and solve for x:

`(390 + x)/(6) = 80`

`390 + x = 480`

`x = 90`