SOLUTION: If Sarah scored an 80,95,75 and an 90 on her first four test , what must she score on her fifth test if she wants An average of 88?

Question 1143128: If Sarah scored an 80,95,75 and an 90 on her first four test , what must she score on her fifth test if she wants An average of 88?
Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52787) (Show Source): You can put this solution on YOUR website!
.

= 88, 80 + 95 + 75 + 90 + x = 5*88 x = 5*88 - (80 + 95 + 75 + 90) x = 100. ANSWER CHECK. = 88.

Answer by greenestamps(13200) (Show Source): You can put this solution on YOUR website!

Here is a way that you might find faster and easier when working a problem like this involving the average of numbers that are "close together".

Comparing each score to the desired average of 88...
80-88 = -8 95-88 = +7 75-88 = -13 90-88 = +2 ----- -12

Overall, her current point total is 12 points below the desired average; that means her next test must be 12 points above the desired average.

ANSWER: She needs a score of 88+12 = 100 on the next test to get an average of 88.
RELATED QUESTIONS
Sarah has grade of 99 and 69 on her first two tests. If she wants an average of at least... (answered by checkley77)
If Katie scored an 80, 83, and an 88 on her first three tests, what must she score on... (answered by MathLover1,greenestamps)
Sarah has grades of 74 and 99 on his first two tests. If she wants an average of at least (answered by ewatrrr)
Susan scored 80, 84, and 92 on her first three algebra test. What must she score on her... (answered by josgarithmetic)
If Katie scores an 80,83 and an 88 on her first 3 tests, what must she score in her... (answered by ikleyn,greenestamps)
Shania has scores of 76 and 81 on her first two tests. If she wants an average of at... (answered by solver91311)
if sarah has grades of 77 and 91 on her first two test. If she wants atleast 80 after her (answered by mananth)
Susan Jacobson has grades of 76 and 81 on her first two algebra tests. If she wants an... (answered by KMST)
Melinda scored 84%, 75% and 77% on her first three tests of the term. What score will she (answered by Boreal,ewatrrr)