Question

Two coal loading trucks handle 9000 tonnes of coal at an efficiency of 90% working 12 hours per day for 8 days. how many hours a day, 3 coal loading trucks should work at an efficiency of 80% so as to load 12000 tonnes of coal in 6 days.

Answer 1

16 h/day
According to question
M1 × D1 × W1 = M2 × D2 × T2 × W1
2 × 12 × 8 × 12000 × 0.9 = 3 × 6 × X × 9000 × 0.8
=> X = 2 x 12 x 8 x 12000 x 0.9/3 x 6 x 9000 x 0.8
= 16h/day