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Question 696112: Tim can stock 2 shelves in 30 minutes. Emma can stock 2 shelves in 45 minutes. If they work together how long will it take to stock 2 shelves?
Answer by ptaylor(2198)   (Show Source):
You can put this solution on YOUR website! Let x=amount of time it takes to stock 2 shelves working together
Then, together, they work at the rate of 2/x shelves per min
Tim works at the rate of 2/30=1/15 shelves per min
Emma works at the rate of 2/45 shelves per min
Together, they work at the rate of 1/15 + 2/45 shelves per min
So, our eq to solve is:
1/15 + 2/45=2/x Multiply each term by 45x
3x+2x=90
5x=90
x=18 min---time it takes both working together to stock 2 shelves
CK
In 18 min, Tim can stock (1/15)*18=18/15=6/5=1 1/5 shelves
In 18 min Emma can stock (2/45)*18=36/45=4/5 shelves
6/5+4/5=2 shelves
2=2
Hope this helps---ptaylor
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