SOLUTION: If the numerator of a fraction is increased by 3, the fraction becomes 3/4. If the denominator is decreased by 7, the fraction becomes 1.

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Question 1159720: If the numerator of a fraction is increased by 3, the fraction becomes 3/4. If the denominator is decreased by 7, the fraction becomes 1.
Found 2 solutions by josgarithmetic, greenestamps:
Answer by josgarithmetic(39617)   (Show Source): You can put this solution on YOUR website!
The fraction


All needed is solve this system for n and d.

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


A solution using logical reasoning and a bit of trial and error with simple arithmetic....

When the denominator is decreased by 7, the fraction becomes 1. That means the denominator is 7 more than the numerator. So the fraction is of the form .

When the numerator is increased by 3, the fraction becomes (equivalent to) 3/4. So the fraction is equivalent to 3/4.

From there you can solve the problem algebraically:






The original fraction is

If you have excellent number sense, you can also work the last part of the problem informally. You know the fraction is equivalent to 3/4. In the fraction 3/4, the difference between numerator and denominator is 1; you want the difference to be 4 (the difference between n+3 and n+7).

So the fraction after you increase the numerator by 3 is ; and that makes the original fraction 9/16.


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