Section: Math Section 2

34) Jake's average test score after 2
tests is 78. What average score must Jake score on the 3rd, 4th, and 5th tests to bring his average up to exactly 87?

1. 85
2. 90
3. 93
4. 95
5. 97

The best way to deal with changing averages is to use the
sum. Use the old average to figure out the total of the first 2 scores. 78 + 78 = 156. Next, figure out the total required by Jake to have an average score of 87 on 5 exams. This is done by multiplying 87 * 5 = 435. Use these two numbers to figure out the total score Jake needs to have on the next 3 exams by subtracting 156 from 435. 435 - 156 = 279. Finally, divide 279 by 3 to figure out the average score to get 93.