Question

A can complete a work in 12 days.A and B both can finish same work in 4 days.B alone can complete the work in

Answer 1

When both will work together they will finish the work in 4 days

Let B finish the work in x days

In 1 day B will do 1/x part of work

In 4 day B will do 4/x part of work

A finish the work in 12 days

In 1 day A will do 1/12 part of work

In 4 day A will do 4/12 part of work

Work of A in 4 day + work of B in 4 day = full work

4/12 + 4/x = 1

4/x = 1-1/3

4/x = 2/3

x = 4*3/2

x = 6

So B alone can finish the work in 6 days

Answer : 6 days