A and B can do a piece of work in 10 h. B and C do it in 15 h, while A and C take 12 h to complete the work. B independently can complete the work in

A's and B,s 1 h work= 1/10
B's and C,s 1 h work = 1/15
and A's and C's 1 h work = 1/12
∴ A's B's and C's 1 h work
= (1/2) x [(1/10) + (1/15) + (1/12)] = (1/2) x (1/4) = 1/8
Hence B's work in 1 h = (1/8) - (1/12) = 1/24
∴ B independently can complete the work in 24 h.