SOLUTION: im not sure what kinda problem this is but i cant figure out HOW to solve it in steps. Jim can fill pool carying buckets of water in 30 min.Sue can do same job in 45 min. and tony

Algebra ->  College  -> Linear Algebra -> SOLUTION: im not sure what kinda problem this is but i cant figure out HOW to solve it in steps. Jim can fill pool carying buckets of water in 30 min.Sue can do same job in 45 min. and tony      Log On


   

Question 91951: im not sure what kinda problem this is but i cant figure out HOW to solve it in steps. Jim can fill pool carying buckets of water in 30 min.Sue can do same job in 45 min. and tony can do it in 1 and 1/2 hours.How quickly can they all do the job together?
Answer by mathispowerful(115) About Me  (Show Source):
You can put this solution on YOUR website!
This is working together problem.
The basic idea is, each person finishes part of the job, and together they finish the whole thing which is represented by 100% which is 1.
Jim: 30min in 1 min Jim can finish 1/30th of the job
Sue 45min in 1 min Sue can finish 1/45th of the job
Tony 90min in 1 min Tony can finish 1/90th of the job
Let's assume it will take them T minutes to finish the job together,
then T%2A%281%2F30+%2B+1%2F45+%2B+1%2F90%29+=+1
where 1%2F30+%2B+1%2F45+%2B+1%2F90 represents the portion of the job that can be finished in one minute working together.
Now solve the equation: multiply 90 on both sides
T(3 + 2+ 1) = 90
6T = 90
T = 15 min
So it will take them 15 minutes to fill the pool working together.