|
Question 135797: An experienced accountant can balance the books twice as fast as a new accountant. Working together it takes the accountants 10 hours. How long would it take the experienced accountant working alone?
Answer by ptaylor(2198)   (Show Source):
You can put this solution on YOUR website! Here I will define balancing the books as the "job"
The new accountant balances the books in x hours so she works at the rate of 1/x of the job per hour
The experienced accountant balances the books in x/2 hours so he works at the rate of 1/(x/2) or 2/x of the job per hour
Together they work at the rate of 1/x+2/x=3/x of the job per hour
Now we are told that in 10 hours working together they can balance the books or get the "job" done, so our equation to solve is:
(3/x)*10=1 (one job, that is) multiply each side by x
x=30 hrs-----------------number of hours it takes the new accountant to do the job working alone
x/2=30/2=15 hours-----------number of hours it takes the experienced accountant to do the job working alone
CK
1/30 + 1/15=3/30=1/10 of the job per hour. So, in 10 hours working together, they can do the job.
Hope this helps---ptaylor
|
|
|
| |
