Question

If 15 men can dig a trench of 9 m long in 30 hours how long will it take 16 men to dig a trench 48 m long

Answer 1

Total work (man-hours per meter) = (15 men × 30 h) / 9 m = 450 / 9 = 50 man‑hours/m.

For 48 m: required = 48 × 50 = 2400 man‑hours. With 16 men: time = 2400 / 16 = 150 hours.

So it will take 150 hours (= 6 days 6 hours).