SOLUTION: Margaret scored 55 points and 65 points on her first two tests on MAT 171. What must she get on the third test to get an average for the three tests of at least 70, so she can end

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Question 1147416: Margaret scored 55 points and 65 points on her first two tests on MAT 171. What must she get on the third test to get an average for the three tests of at least 70, so she can end with a C? All tests have a maximum of 100 points. You must set up your inequality and solve algebraically.
Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.

%2855+%2B+65+%2B+x%29%2F3 >= 70


55 + 65 + x >= 3*70


x >= 210 - 55 - 65 = 90.


ANSWER.  She must get at least 90.


Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


Her first test is 15 points short of the average she wants; her second test is 5 points short. With the two tests together, she is 20 points short of the average she wants.

The third test must make up that shortfall; her score must be 20 points ABOVE the average she wants.

ANSWER: 70+20 = 90