SOLUTION: Sam can stain his deck in 9 hours. His sister Grace can stain the deck in 12 hours. How many hours will it take them to stain the deck if they work together?

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Sam can stain his deck in 9 hours. His sister Grace can stain the deck in 12 hours. How many hours will it take them to stain the deck if they work together?       Log On


   

Question 1010359: Sam can stain his deck in 9 hours. His sister Grace can stain the deck in 12 hours. How many hours will it take them to stain the deck if they work together?

Answer by josgarithmetic(39613) About Me  (Show Source):
You can put this solution on YOUR website!
The sum of their rates is their combined rate. Reciprocal of this rate is the time for "staining his deck".

Sam stains his deck at the rate 1%2F9 deck per hours.
Grace stains the deck at the rate of 1%2F12 deck per hours.