SOLUTION: Can I please have help on this problem? bill bean has grades of 77 and 91 on his first two biology tests. what possible scores could he make on his third test so that his average

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Question 834215: Can I please have help on this problem?
bill bean has grades of 77 and 91 on his first two biology tests. what possible scores could he make on his third test so that his average is at least 85?
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
first 2 scores are 77 and 91.
average needs to be at least 85.
there will be 3 scores total.

you get 77 + 91 + x = 85 * 3
this becomes:
168 + x = 255
subtract 168 from both sides of this equation to get:
x = 255 - 168
you get x = 87

he needs to get at least an 87 in order to get an overall average of at least 85.

77 + 91 + 87 = 255

255 / 3 = 85