Question

The average of Paula's two test scores must be 80 or more for her to get at least a B in the class. She got a 72 on her first test. What grades can she get on the second test to make at least a B in the class?

Answer 1

`88`

Explanation:

I'll use the average formula to find the answer to this.

`"average" = ("sum of grades")/("number of grades")`

She had a test with a score of `72`, and a test with an unknown score `x`, and we know that her average has to be at least `80`, so this is the resulting formula:

`80 = (72 + x)/(2)`

Multiply both sides by `2` and solve:

`80 xx 2 = (72 + x)/cancel2 xx cancel2`

`160 = 72 + x`

`88 = x`

So the grade she can make on the second test to get at least a `"B"` would have to be a `88%`.