posted by Luanne .
A painter can paint a racquetball court in 8 hours. His assistant needs an additional 2 hours to paint the same court working by himself. How long will it take both of them working together to paint the court.
painter's rate --> court/8
assistant's rate --> court/2
combined rate = court/8 + court/2 = 5court/8
time with combined rate = court/(5court/8)