SOLUTION: I have a 64 a 79 and a 75 What do I need to have a 75 average?

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Question 854315: I have a 64 a 79 and a 75
What do I need to have a 75 average?
Found 2 solutions by LinnW, richwmiller:
Answer by LinnW(1048) About Me  (Show Source):
You can put this solution on YOUR website!
The average is the total of the grades divided by the number of grades.
Set x = the new grade.
( 64 + 79 + 75 + x )/4 = 75
(218 + x)/4 = 75
multiply each side by 4
218 + x = 300
add -218 to each side
x = 82

Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
(64+79+75+x)/4=75
x=82
or 75-64-(79-75)=7
75+7=82