SOLUTION: Mike can assemble a computer table in 40 minutes and I can do it in 60 minutes. If Mike works for 20 minutes before I join him, how long will it take us to finish?

Question 188568: Mike can assemble a computer table in 40 minutes and I can do it in 60 minutes. If Mike works for 20 minutes before I join him, how long will it take us to finish?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Mike can assemble a computer table in 40 minutes and I can do it in 60 minutes. If Mike works for 20 minutes before I join him, how long will it take us to finish?
;
Let t = time required to finish, working together (in minutes)
:
Let the completed job = 1
:
(t+20) = Mike's working time
:
A shared work equation:
+ = 1
multiply equation by 120; results:
3(t+20) + 2t = 120
:
3t + 60 + 2t = 120
:
5t = 120 - 60
:
5t = 60
t =
t = 12 minutes to finish
;
:
Check solution (Mike works for 32 min)
(32/40) + 12/60 =
.8 + .2 = 1
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