Question

if 1 is added to the numerator of a fraction,it becomes 1/5;if 1 is taken from the denominator,it becomes 1/7,find the fraction.

Answer 1

(n+1)/d = 1/5 
n/(d-1) = 1/7 

5(n+1) = d 
7n = d-1 

5n - d = -5 
7n - d = -1 

2n = 4 
n=2 
d=15 

Check: 
n/d = 2/15 

3/15 = 1/5 
2/14 = 1/7

Answer 2

I hope this is helpfull for you