SOLUTION: Dave can do the job in 30 days. Giles can do it in 40 days, and Jon can do it 60 days. How long will it take them if they work together?

Question 956010: Dave can do the job in 30 days. Giles can do it in 40 days, and Jon can do it 60 days. How long will it take them if they work together?
Answer by ptaylor(2198) (Show Source): You can put this solution on YOUR website!
Dave can do the job in 30 days. Giles can do it in 40 days, and Jon can do it 60 days. How long will it take them if they work together?
Let x=amount of time needed for the three to do the job when they work together
Then they work at the rate of 1/x of the job per day
Dave works at he rate of 1/30 of the job per day
Giles works at the rate of 1/40 of the job per day
Jon works at the rate of 1/60 of the job per day
Sooooo
1/30 + 1/40 + 1/60= 1/x multiply each term by 120x
4x+3x+2x=120
9x=120
x=13 1/3 days---time needed if they work together
CK
In 13 1/3=40/3 days, Dave completes (40/3)(1/30)=4/9 of the job
In 40/3 days, Giles completes (40/3)(1/40)=1/3=3/9 of the job
In 40/3 days, Jon completes (40/3)(1/60) =2/9 of the job
4/9 + 3/9 +2/9=1 job completed:)
Hope this helps----ptaylor

RELATED QUESTIONS
alma can do a job in 6 days. rachel can do job in 12 days. how long it will take if they... (answered by nihar*2013)

If Sam can do a job in 4 days, Lisa can do the same job in 6 days, and Tom can do the job (answered by stanbon)

Alma can do the job in 6 days while Rachel can do the same. In 12 days. How long will it... (answered by Cromlix)

How would I find the answer to these 2 problems: If Tom can do a job in 2 days, Mike... (answered by ankor@dixie-net.com)

If Sam can do a job in 4 days that Lisa can do in 6 days and Tom can do in 2 days, how... (answered by ntnk)

If Jon can paint a house in 5 days and James can do same in 8 days, how many days will it (answered by Alan3354)

If Harry can do a job in 2 days, and Sally can do the job in 4 days, and Henry can do... (answered by stanbon)

If Clyde can do a job in 8 days and Irv can do the same job in 3 days, how long would it... (answered by josgarithmetic)

4.It will take Lulu six days to clear her lot. Her son Nike, can do the same job in 5... (answered by josgarithmetic)