Question 871188
1/x+1/(4x)=1/12
4/4x+1/4x-1/12
5/4x=1/12
60=4x old
15=x new 
checks
1/15+1/60=1/12
4/60+1/60=1/12
5/60=1/12
ok
12/60+12/15=1
1/5+4/5=1

ok