posted by Math(: on .
John has scores of 88,73,90,85,93 on five math quizzes. What scores must john earn on the next math quiz to have a mean quiz score of exactly 88?
The mean means:
Add all numbers and then divide how many numbers there are
88 + 73 + 90 + 85 + 93 = 429
429 / 5 = 85.8 <--- that is the mean of what you got.
However, the question asks you for what future grade you must make on the next test to average an 88% with those current grades. So this will tell us that we have to make at least in the 90's.
So we try 99%
88 + 73 + 90 + 85 + 93 + '99' = 528
then again we must divide by amount of numbers. Which there are 6 now, instead of 5.
528 / 6 = 88
So, in order for a student to receive an average of an 88%, they must make a 99% on the next test.
Johns next quizz will be 6-th.
If He want 88 points in tis case must be:
(88+73+90+85+93+99)/6= 528/6 = 88