Question

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?

Answer 1

The mean means:

Add all numbers and then divide how many numbers there are

First Step:

88 + 73 + 90 + 85 + 93 = 429

Second Step:

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.


Cheers!

Answer 2

Johns next quizz will be 6-th.
If He want 88 points in tis case must be:

(88+73+90+85+93+x)/6=88

88+73+90+85+93+x=88*6

429+x=528

x=528-429

x=99

(88+73+90+85+93+99)/6= 528/6 = 88