Question

Trent wants a MEAN grade of 90% or better on his mathematics test. His test grades so far are 85%, 88%, 92%, and 90%. What is the lowest grade he can get on his next test and still have a mean grade of 90%?

Answer 1

95%

Explanation:

Current MEAN = 85 + 88 + 92 + 90/4 = 88.75 %

Lets assume needed score is 92%

Mean with assume needed score: 85 + 88 + 92 + 90 + 92/5 = 89.4%

Lets assume needed score is 93%

Mean with assume needed score: 85 + 88 + 92 + 90 + 93/5 = 89.6%

Lets assume needed score is 94%

Mean with assume needed score: 85 + 88 + 92 + 90 + 94/5 = 89.8%

Lets assume needed score is 95%

Mean with assume needed score: 85 + 88 + 92 + 90 + 95/5 = 90%