SOLUTION: Two people together can do a certain job in twenty minutes. If one of them can do the job alone in forty-five minutes, how long will the other person take to do the job alone?
Algebra.Com
Question 121716: Two people together can do a certain job in twenty minutes. If one of them can do the job alone in forty-five minutes, how long will the other person take to do the job alone?
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Two people together can do a certain job in twenty minutes. If one of them can do the job alone in forty-five minutes, how long will the other person take to do the job alone?
---------------
Together DATA:
Time = 20 min/job ; Rate = 1/20 job/min
--------------
One person DATA:
Time = 45 min/job ; Rate = 1/45 job/min
---------------
2nd person DATA:
Time = x min/job ; RAte = 1/x job/min
---------------------
EQUATION:
rate + rate = together rate
1/45 + 1/x = 1/20
Multiply thru by 180x to get:
4x + 180 = 9x
5x = 180
x = 36 min (time for the 2nd person to do the job alone)
===========
Cheers,
Stan H.
RELATED QUESTIONS
One person can do a certain job in twenty-one minutes, and another person can do the same (answered by checkley71)
One person can do a certain job in 15 minutes, and another person can do the same job in... (answered by Maths68)
three people together can do certain job in three hours. Of one of them can the job in... (answered by josgarithmetic)
One person can do a certain job in ten minutes, and another person can do the same job in (answered by stanbon,ikleyn)
Joe can do a certain job in 21 minutes. Bob can do the same job in 28 minutes. How long... (answered by solver91311)
If two people can do a job in 12 minutes. And one person takes 30 minutes how long does... (answered by ntnk)
George can do a certain job in 70 minutes while Abe can do the same job in 30 minutes.... (answered by nerdybill)
Three people together can do a certain job in three hours. If one of them can do the job... (answered by josgarithmetic)
One person can do a certain job in one-half hour, and another person can do the same job... (answered by nerdybill)