SOLUTION: Jane takes 4 hours to do a job that Alice can do in 3 hours. If Jane works 1/2 hour before Alice joins her, how long will it take the two of them to finish the job?

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Jane takes 4 hours to do a job that Alice can do in 3 hours. If Jane works 1/2 hour before Alice joins her, how long will it take the two of them to finish the job?      Log On


   



Question 587005: Jane takes 4 hours to do a job that Alice can do in 3 hours. If Jane works 1/2 hour before Alice joins her, how long will it take the two of them to finish the job?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Jane takes 4 hours to do a job that Alice can do in 3 hours.
If Jane works 1/2 hour before Alice joins her, how long will it take the two of them to finish the job?
:
Let t = time required to finish the job together
then
(t+.5) = total time worked by Jane
:
Let the completed job = 1
:
Each girl will do a fraction of the job, the two fractions add up to 1
t%2F3 + %28%28t%2B.5%29%29%2F4 = 1
multiply by 12
12*t%2F3 + 12*%28%28t%2B.5%29%29%2F4 = 12
Cancel the denominators
4t + 3(t+.5) = 12
3t + 4t + 1.5 = 12
7t = 12 - 1.5
7t = 10.5
t = 10.5%2F7
t = 1.5 hrs to finish the job together
:
:
Check (J works 2 hrs)
2%2F4 + 1.5%2F3 = 1
.5 + .5 = 1