Let the numerator be
x and the denominator be
y.
From the given information, we have,
x+2y=12andxy−1=13or,x+2y=12=>2(x+2)=y=>y=2x+4....(i)Also,xy−1=13=>3x=y−1....(ii)
Using substitution method,
Substituting equation (i) in equation (ii), we get,
3x=2x+4−1=>x=3
Substituting x=3 in equation (i), we get,
y=2x+4=>y=2(3)+4=>y=6+4=>y=10
Thus, the original fraction is xy=310