Question 1142779
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When working a problem like this involving the average of numbers that are "close together", it is often easy to solve the problem by comparing each individual number to the average.<br>
In this problem, the desired average is 85; the given scores are 80, 83, and 88.<br>
80 compared to the desired average is -5; 83 is -2; 88 is +3.<br>
All together the three tests compared to the average are (-5)+(-2)+(+3) = -4.<br>
So to get the desired average the next test must be +4.<br>
ANSWER: 85+4 = 89