2 men can complete a work in 15 days working 8 hours a day. The same work is completed by 3women working 4 hours a day for 16days. Find the time taken by a boy whose efficiency is 50% more than a woman and working 2 hours a day?

First find the work: 2 men × 15 days × 8 hours = 240 man-hours. Same work done by 3 women × 16 days × 4 hours = 192 woman-hours. So 240 man-hours = 192 woman-hours, meaning 1 man = 0.8 woman or 1 woman = 1.25 men. Boy's efficiency is 50% more than woman, so 1 boy = 1.5 women = 1.5 × 1.25 = 1.875 men. Time = 240 / (1.875 × 2) = 64 days.