Damon has taken six history tests so far this year. The tests are out of twenty-five points, and he has gotten the following scores.

21, 20, 24, 19, 20, 24

What must Damon score on his seventh test in order to have a mean of 21?

Question

Damon has taken six history tests so far this year. The tests are out of twenty-five points, and he has gotten the following scores.

21, 20, 24, 19, 20, 24

What must Damon score on his seventh test in order to have a mean of 21?

Vocaloid · Answer

Mean = sum/number of items

Therefore, sum = mean * number of items

So to get a mean of 21 on 7 tests, he must have a total of 21 * 7 points across all tests. Multiply this out, then subtract the other six test scores to get the remaining score.