SOLUTION: JOhn does a task in 30 minutes, Jennifer does in 45 minutes and Caryn in 1 1/2 hour. How long would it take for the three of them to do it if they do it together?

Question 56849: JOhn does a task in 30 minutes, Jennifer does in 45 minutes and Caryn in 1 1/2 hour. How long would it take for the three of them to do it if they do it together?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
JOhn does a task in 30 minutes, Jennifer does in 45 minutes and Caryn in 1 1/2 hour. How long would it take for the three of them to do it if they do it together?
:
Get everything in minutes: Caryn 1.5 hr = 90 min
:
Let the completed job = 1
:
Let x = time required when they all work together:
:
The equation:
= 1
:
We can eliminate the denominators by mult eq by 90, we then have:
3x + 2x + x = 90
6x = 90
x = 15 minutes to complete the job:
:
Check:
15/30 + 15/45 + 15/90 =
3/6 + 2/6 + 1/6 = 1
:

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