Question

The sum of the numerator and denominator of a fraction is 12. If 1 is added to both the numerator and denominator the fraction becomes 3/4. Find the fraction.

Answer 1

Let call our fraction xy, we know that:

x+y=12

and

xy+3=12

from the second:

x=12(y+3)

into the first:

12(y+3)+y=12

y+3+2y=24

3y=21

y=213=7

and so:

x=12−7=5

Answer 2

Let call our fraction xy, we know that:

x+y=12

and

xy+3=12

from the second:

x=12(y+3)

into the first:

12(y+3)+y=12

y+3+2y=24

3y=21

y=213=7

and so:

x=12−7=5