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 188603: 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 ptaylor(2198) (Show Source): You can put this solution on YOUR website!
Let x=amount of time it will take you and Mike to finish
Mike works at the rate of 1/40 computer per min
You work at the rate of 1/60 computer per min
Together you and Mike work at the rate of 1/40 +1/60=3/120 + 2/120=5/120=1/24 computer per min
Before you start, Mike as already assembled (1/40)*20=1/2 of the computer, leaving 1/2 of the computer yet to be done. So the question is how long will it take you and Mike working together to do the remaining half of the computer
Now our equation to solve is:
(1/24)*x=1/2 (1/2 of the computer, that is) Multiply each side by 24
x=12 min------------------amount of time it will take you and Mike to finish

CK
(1/24)*12=1/2
1/2=1/2
Hope this helps---ptaylor
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