SOLUTION: Two men together can do a piece of work in one hour and twenty minutes. The first man can do the work alone in three hours. How long would it take the second man alone to do the wo

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Two men together can do a piece of work in one hour and twenty minutes. The first man can do the work alone in three hours. How long would it take the second man alone to do the wo      Log On


   



Question 244052: Two men together can do a piece of work in one hour and twenty minutes. The first man can do the work alone in three hours. How long would it take the second man alone to do the work? (I came up with 1 hr.29 mins. but I don't think that's right).
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Two men together can do a piece of work in one hour and twenty minutes.
The first man can do the work alone in three hours. How long would it take the second man alone to do the work?
:
Because of the fractional hr do the problem in minutes
Working together 80 min
1st man alone 180 min
Let t = 2nd man alone
Let the completed job = 1
:
80%2F180 + 80%2Ft = 1
Multiply by 180t
80t + 180(80) = 180t
80t + 14400 = 180t
14400 = 180t - 80t
14400 = 100t
t = 144 min, 2hr 24 min