A can do a piece of work in 8 days working 12 hours per day. If B is two-thirds as efficient as A, then in how many days B alone do the same piece of work, working 4 hours per day?

Question: A can do a piece of work in 8 days working 12 hours per day. If B is two-thirds as efficient as A, then in how many days B alone do the same piece of work, working 4 hours per day?Solution:Time taken by A alone to do the work = 8×12 = 96 hrs. Since B is 2/3 efficient as A, so time taken by B is 3/2 times of A = ( 96×3/2 ) hrs = 144 hrs.∴ Required days = ( 144/4 ) = 36 days.