math
posted by Alyssa on .
I have a 76 average right now, what grades do I need to get if i have 5 more tests and need to get an 85 average?

Depends on how many tests you have already taken. If you have taken n tests so far, then the average on the next 5 tests must be m, where
76n + 5m = 85(n+5)
m = 85 + 9/5 n
Assuming all tests are weighted equally. As you can see, the more low scores you have contributing to the 76 average, the higher grade it will take to achieve a final 85.
In fact, if you have 9 low scores, there is no way to raise your average to 85 with 5 more tests.
9*76 = 684
14*85 = 1190
Points needed: 506
no way to get that many points in 5 tests.