SOLUTION: If Kevin can do a job in five hours and Carrie can do the same job in 4 hours how long will it take for them to do the job together? Could you please explain your answer as well

Algebra ->  Equations -> SOLUTION: If Kevin can do a job in five hours and Carrie can do the same job in 4 hours how long will it take for them to do the job together? Could you please explain your answer as well      Log On


   

Question 367163: If Kevin can do a job in five hours and Carrie can do the same job in 4 hours how long will it take for them to do the job together? Could you please explain your answer as well
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Find the hourly rate of each person.
If Kevin can do the job in 5 hours, then he can do 1%2F5 of the job in 1 hour.
If Carrie can do the job in 4 hours, then she can do 1%2F4 of the job in 1 hour.
So together, they can do 1%2F5%2B1%2F4+=+9%2F20 of the job in 1 hour.
This means that it will take them 20%2F9+=+22%2F9 hours to complete the job together.
22%2F9hours = 2hours,13minutes and 20seconds.