Question 588010: The question states the following: The mean of Wes's first 4 math tests is 88. However, he wants to raise his average to a 90. What score will Wes have to make on his 5th test in order to have an overall mean of 90?
I am thinking that his previous test scores could have been all 88s because 88+88+88+88= 352. 352 divided by 4 is 88. And then the average of that is still an 88, like it said they were in the problem. So what I thought was that, if each test was indeed an 88, then he was 2 points away from a 90 on each of the four tests he took. So i lined up the four test scores of 88 and to the side, I said (+2) in parenthesis next to each score. I did that because if you add 2 and 88, you get 90. So, if there were 4 test scores, and he needed two more points on each test to get a 90, that's 4 times 2 to get 8. Add 8 to 90 and you get 98. To check my work, I took the four 88% tests PLUS the new 98% and found the average of those. In other words, 88+88+88+88+98= 450. 450 divided by 5= 90. And 90 is the new average/mean grade that we want. I want to make sure this is correct. Thank you very much for your help! I really appreciate it!
Answer by nerdybill(7384)   (Show Source):
You can put this solution on YOUR website! The question states the following: The mean of Wes's first 4 math tests is 88. However, he wants to raise his average to a 90. What score will Wes have to make on his 5th test in order to have an overall mean of 90?
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Your answer is correct. However, your logic seems a little complex.
.
Let x = score of 5th test
then
(88+88+88+88+x)/5 = 90
(352+x)/5 = 90
multiplying both sides by 5:
(352+x) = 450
x = 450-352
x = 98
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