SOLUTION: Susan can paint a room in 4 hours. Her younger sister Kay can do the same job in 6 hours. In how many hours can they do the job if they work together? Thanks!

Algebra ->  Graphs -> SOLUTION: Susan can paint a room in 4 hours. Her younger sister Kay can do the same job in 6 hours. In how many hours can they do the job if they work together? Thanks!      Log On


   

Question 735650: Susan can paint a room in 4 hours. Her younger sister Kay can do the same job in 6 hours. In how many hours can they do the job if they work together?
Thanks!
Answer by checkley79(3341) About Me  (Show Source):
You can put this solution on YOUR website!
1/4+1/6=1/x
(6+4)/(4*6)=1/x
10/24=1/x cross multiply.
10x=24
x=24/10
x=2.4 hours working together.