3 adults and 5 children take 4 hours to clean the swimming pool. The same job can be done by 5 adults and 6 children in 3 hours. How long will it take 1 adult to clean the swimming pool alone? How long will it take 1 child to do the same job alone?
3/a + 5/c = 1/4
5/a + 6/c = 1/3
Now just solve for a and c.