SOLUTION: If you averaged 76% on two 100 point tests, what would you have to score on the next 80 point test to raise your average to 80%?

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Question 229554: If you averaged 76% on two 100 point tests, what would you have to score on the next 80 point test to raise your average to 80%?

Answer by ankor@dixie-net.com(12692) About Me  (Show Source):
You can put this solution on YOUR website!
If you averaged 76% on two 100 point tests, what would you have to score on the next 80 point test to raise your average to 80%?
:
Let x = score required to accomplish this:
:
%28.76+%2B+.76+%2B+%28x%2F80%29%29%2F3 = .80
Multiply equation by 3
.76 + .76 + x%2F80 = 3(.80)
:
1.52 + x%2F80 = 2.40
:
Multiply equation by 80
1.52(80) + x = 2.4(80)
121.6 + x = 192
x = 192 - 121.6
x = 70.4 has to be scored on this 80 point test
:
:
Check solution
%28.76+%2B+.76+%2B+%2870.4%2F80%29%29%2F3 = .80
%28.76+%2B+.76+%2B+.88%29%2F3 = .80
2.4%2F3 = .8 which is 80%