SOLUTION: I do not understand how to set up this problem. Your quiz grades are 73,75,89,and 91. What is the lowest grade you can obtain on the last quiz and still achieve an average of at

Question 210199This question is from textbook
: I do not understand how to set up this problem.
Your quiz grades are 73,75,89,and 91. What is the lowest grade you can obtain on the last quiz and still achieve an average of at least 85?This question is from textbook

Found 2 solutions by jim_thompson5910, stanbon:
Answer by jim_thompson5910(21667) (Show Source):
You can put this solution on YOUR website!
Let x = grade of last quiz

Remember, the average of 5 numbers is simply the sum of those 5 numbers divided by 5. In other words, the average of 73,75,89,91, and 'x' (the last quiz score) is

Since you want "at least 85", this means that the average has to be greater than or equal to 85 like so

I'll let you take it from here. Let me know if you need more help.

Answer by stanbon(48545) (Show Source):
You can put this solution on YOUR website!
Your quiz grades are 73,75,89,and 91. What is the lowest grade you can obtain on the last quiz and still achieve an average of at least 85?
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Let the grade you need be "x":
Equation:
The average of the 5 grades must be 85:
73+75+89+91+x = 5*85
x = 425-(73+75+89+91)
x = 97 (Lowest grade on last quiz to achieve
an average of at least 85)
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Cheers,
Stan H.