A and B can do a piece of work in 36 days. B and C can do the same work in 60 days. A and C can do the same work in 45 days. In how many days can B alone complete the same work?

90

A + B = 36 days,

B + C = 60 days,

A + C = 45 days,

⇒ Adding all the efficiency, we get,

 2(A + B + C) = 12,

⇒ A + B + C = 6,

Putting value of A + C, we get B,

⇒ B + 4 = 6

⇒ B = 2

Hence, time required by B to complete the work alone = \(\frac{180}{2}\) = 90 days.            ..(\(\frac{Work}{Efficiency}\) = Time )