SOLUTION: Doug received the following scores on his first four tests: 77%, 83%, 89%, and 86%. What score must he get on his fifth test to average 85% for all five tests?

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Question 900985: Doug received the following scores on his first four tests: 77%, 83%, 89%, and 86%. What score must he get on his fifth test to average 85% for all five tests?
Found 2 solutions by Jc0110, Alan3354:
Answer by Jc0110(165) About Me  (Show Source):
You can put this solution on YOUR website!
Let x to be the score for fifth test.
Average+=+SumOfNumbers%2FNumberOfTerms
85+=+%2877+%2B+83+%2B+89+%2B+86+%2B+x%29%2F5
425+=+77+%2B+83+%2B+89+%2B+86+%2B+x
x=90%

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Doug received the following scores on his first four tests: 77%, 83%, 89%, and 86%. What score must he get on his fifth test to average 85% for all five tests?
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85*5 = 425
77 + 83 + 89 + 86 = 335
425 - 335 = 90%