A and B together can complete the same work in 36 days. B and C together can complete the same work in 60 days. A and C together can complete the same work in 45 days. In how many days, B alone can complete the same work?

90 days

A + B = 36 days,

B + C = 60 days,

C + A = 45 days,

⇒ Adding all the efficiencies, we get,

⇒ 2(A + B + C) = 12,

⇒ A + B + C = 6,    (Efficiency)

⇒ 5 + C = 6,

⇒ C = 1,

Similarly,

⇒ B + C = 3,

⇒ B + 1 = 3,

⇒ B = 2,

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