SOLUTION: there are fifteen question how many can i get wrong but still get a 85 or better?

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Question 607960: there are fifteen question how many can i get wrong but still get a 85 or better?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

Note: If there were 20 Questions (each accounting for 5%)one could get 3 wrong

 Let x represent how many wrong but still get a 85 or better?

Sets Up the Proportion

 3%2F20+=+x%2F17     |Cross Multiplying to solve

    20x = 17·3

     x = 17·3/20

     x = 2.55 , can only have 2 wrong to get 85 or better