SOLUTION: Katie must take five exams in a math class. If her scores on the first four exams are 68, 66, 82, and 80, then answer the following questions. The maximum score on an exam is

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Question 420292: Katie must take five exams in a math class. If her scores on the first four exams are 68, 66, 82, and 80, then answer the following questions.
The maximum score on an exam is 100 points. If it is not possible for Katie to achieve the required score on the exam, type np in the answer blank.

What score must Katie get on the fifth exam for her overall mean to be at least 70?
What score must Katie get on the fifth exam for her overall mean to be at least 80?
What score must Katie get on the fifth exam for her overall mean to be at least 90?
Answer by vleith(2983) (Show Source):
You can put this solution on YOUR website!
Use the same set of steps to find your answer. I will do the first quetion, you can use the same process to solve the other 2.
You are given 4 test scores. You are given a average for 5 test scores. You are then asked if it is possible to achieve the average score over 5 tests given the scores on the first 4. The highest score you can get on the 5th test is 100.
So use this formula

This is the first question's average

So if Katie socres a 54 or higher on the 5th test, she can achieve at least a 70 average.
Use the same process for the other two. You do the work to show she can't make an 80 or a 90.
If the score she needs to get is more than 100, she can't make that average.