SOLUTION: It takes Sally 15 minutes to pick apples from the tree in the backyard. Lisa can do it in 25 minutes. How long will it take them working together?

Algebra ->  Rate-of-work-word-problems -> SOLUTION: It takes Sally 15 minutes to pick apples from the tree in the backyard. Lisa can do it in 25 minutes. How long will it take them working together?      Log On


   



Question 414253: It takes Sally 15 minutes to pick apples from the tree in the backyard. Lisa can do it in 25 minutes. How long will it take them working together?
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
sally 15 minutes
Lisa 25 minutes
..
Sally does 1/5 of job in 1 minute
Lisa does 1/25 of the job in 1 minute
..
Together they do 1/15 +1/25 of the job in 1 minute
LCD = 75
(5+3)75 of the job in 1 minute
8/75 of the job in 1 minute
so together they take 75 /8 minutes
9 3/8 minutes