trey can clean a room in 40 minutes. his brother Marcus can clean the same room in 20 minutes. how long will it take them to clean the room if they work together?

Question

tkhunny · Answer

You have "rooms per minute"..  Change to "Minutes per room" and the world will be a clearer place.

kasep10 · Answer

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directrix · Answer

@steven513 

Look at the attachment which shows the set-up for this type problem.

directrix · Answer

Trey does 1/40 of the job per minute
Marcus does 1/20 of the job per minute
x is the amount of time the two complete the job working togethr

Following the pattern:

1/40  +  1/20  = 1/x

1/40  +  2/40 = 1/x

3/40 = 1/x

Solve for x.

Post what you get, okay?

@steven513

eliesaab · Answer

Practice problems of this kind on http://www.saab.org/mathdrills/workcompletion.cgi