SOLUTION: For some reason my mind is drawing a blank. The question is: Candice had scores of 95, 82, 93 and 84 on her first four exams of the semester. What score must she obtain on the f

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Question 176906This question is from textbook Elementary and intermediate algebra
: For some reason my mind is drawing a blank. The question is:
Candice had scores of 95, 82, 93 and 84 on her first four exams of the semester. What score must she obtain on the fifth exam to have an average of 90 or better for the 5 exams. How do you set this problem up? THanks
 This question is from textbook Elementary and intermediate algebra

Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!


1st score = 95
2nd score = 82
3rd score = 93
4th score = 84
5th score = x

Add them up and divide by 5

%2895%2B82%2B93%2B84%2Bx%29%2F5

Set that greater than or equal to the desired average, 90

matrix%281%2C1%2C+%2895%2B82%2B93%2B84%2Bx%29%2F5+%3E=+90%29

Simplify the numerator on the left:

matrix%281%2C1%2C+%28354%2Bx%29%2F5+%3E=+90%29

Multiply both sides by LCD of 5 to 
clear of fractions:

matrix%281%2C1%2C+5%28%28354%2Bx%29%2F5%29%3E=+5%2890%29%29

Cancel 5's on the left, multiply on
the right:

matrix%281%2C1%2C+cross%285%29%28%28354%2Bx%29%2Fcross%285%29%29%3E=+450%29

matrix%281%2C1%2C+354%2Bx+%3E=+450%29

matrix%281%2C1%2C+x%3E=+96%29%29

So it'll take a score equal to or greater than 96 
on the 5th test to bring Candice's average up to 90.

Edwin