Question

Herman and Rosie need to wash the walls on the side of the school. Herman has a power washer, which could complete the job in 10 hours. Rosie has a manual scrubber, which could complete the job in 15 hours. If they work together, how many hours will it take them to clean the wall?

Answer 1

It would take them 6 hours. Six hours is 3/5 of Herman’s required time. 6 hours is 2/3 of Rosie’s, so 3/5 +2/5= the project being complete.