SOLUTION: Working alone, Leo can clean the windows in the living room in 30 minutes; it would take Margaret 20 minutes to do the same task. How long would it take them working together?

Question 1005970: Working alone, Leo can clean the windows in the living room in 30 minutes; it would take Margaret 20 minutes to do the same task. How long would it take them working together?
Found 2 solutions by fractalier, Alan3354:
Answer by fractalier(6550) (Show Source): You can put this solution on YOUR website!
The set up looks like this
t/20 + t/30 = 1
Multiply by 60 and get
3t + 2t = 60
5t = 60
t = 12 minutes working together
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
Working alone, Leo can clean the windows in the living room in 30 minutes; it would take Margaret 20 minutes to do the same task. How long would it take them working together?
-------------
Leo cleans 1/30 of a window per minute.
Mar cleans 1/20 of a window per minute.
---
Together, they clean 1/30 + 1/20 per minute.
= 50/600 = 1/12 window per minute
--> 12 min/window
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