SOLUTION: On an examination of n questions a student answers correctly 15 of the first 20 questions. Of the remaining questions he answers one third correctly. All the questions have the sam

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Question 868235: On an examination of n questions a student answers correctly 15 of the first 20 questions. Of the remaining questions he answers one third correctly. All the questions have the same credit. If the student's mark is 50%, what is the value of n?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
%2815+%2B+n%2F3%29%2Fn+=+.50
15 + n/3 = n/2
15 = 2/12 n
%2812%2F2%2915+=+n
90 = n
CHECKING our answer***
(15 + 30)/90 = .50 0r 50%
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