SOLUTION: Jo needs an 85% average on her five math tests. She earned 99%, 85%, 79%, and 88% on her first four tests. What score must she earn on her fifth test in order to have an average of

Question 265133: Jo needs an 85% average on her five math tests. She earned 99%, 85%, 79%, and 88% on her first four tests. What score must she earn on her fifth test in order to have an average of exactly 85% for all five tests?
Found 2 solutions by rfer, checkley77:
Answer by rfer(16322) (Show Source): You can put this solution on YOUR website!
(99+85+79+88+x)/5=85
351+x/5=85
351+x=85*5
351+x=425
x=74%
Answer by checkley77(12844) (Show Source): You can put this solution on YOUR website!
(99+85+79+88+x)/5=85
(351+x)/5=85
351+x=85*5
351+x=425
x=425-351
x=74 is the test score required on the fifth test for the 85 average.
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