SOLUTION: If a certain number is addedto the numerator and denminator of 7/15, the result is 1/3, find the number?

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Question 225857: If a certain number is addedto the numerator and denminator of 7/15, the result is 1/3, find the number?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
f a certain number is added to the numerator and denominator of 7/15, the result is 1/3, find the number?
:
let x = "the number"
:
%28x%2B7%29%2F%28x%2B15%29 = 1%2F3
cross multiply
3(x + 7) = 1(x + 15)
3x + 21 = x + 15
3x - x = 15 - 21
2x = -6
x = -3 is the certain number
:
:
Check
%28-3%2B7%29%2F%28-3%2B15%29 = 1%2F3
%284%29%2F%2812%29 = 1%2F3