SOLUTION: Going for a C. Professor Williams gives only a midterm exam and a final exam. The semester average is computed by taking 1/3 of the midterm exam score plus  2/3 of the final ex

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Question 260241: Going for a C. Professor Williams gives only a midterm
exam and a final exam. The semester average is
computed by taking 1/3 of the midterm exam score plus 
2/3 of the final exam score. To get a C, Stacy must have a
semester average between 70 and 79 inclusive. If Stacy
scored only 48 on the midterm, then for what range
of scores on the final exam will Stacy get a C?
I can not come up with the correct formula
70 < ? < 79

Answer by drk(1908) About Me  (Show Source):
You can put this solution on YOUR website!
The inequality we need is the following:
70+%3C+%281%2F3%29m+%2B+%282%2F3%29f+%3C+79
since m = 48, we then get
70+%3C+%281%2F3%29%2A48+%2B+%282%2F3%29f+%3C+79
which is
70+%3C+16+%2B+%282%2F3%29f+%3C+79
subtract 16 from all parts to get
54+%3C+%282%2F3%29f+%3C+63
multiply all parts by 3/2 to get
81+%3C+f+%3C+94.5