Two coal loading machines each working 12 h per day for 8 days handle ...
Two coal loading machines each working 12 h per day for 8 days handle 9000 tonnes of coal with an efficiency of 90%: while 3 other coal loading machines at an efficiency of 80% are set to handle 12000 tonnes of coal in 6 hrs/ days. Find how many hours per day each should work? Time and work