Question

A and B together complete work in 4 days. if a alone can work in 12 days then on how many days can B alone complete work

Answer 1

time taken by a and b to complete the work = 4 days
work done by a and b in 1 day = 1/4 day
time taken by A to complete the work = 12 days
work done by a in 1 day = 1/12day
work done by B in 1 day = work done by a and b in 1 day - work done by a in 1 day
1/4-1/12
LCM of 4 and 12= 24
6/24-2/24 = 4/24 = 1/6
b alone can do work in 1÷1/6 = 6 days