SOLUTION: It takes a boy 45 minutes to deliver the newspaper on his route, however if his sister helps, It takes only 20 minutes.How long they would it take his sister to deliver the newspap

Question 1049625: It takes a boy 45 minutes to deliver the newspaper on his route, however if his sister helps, It takes only 20 minutes.How long they would it take his sister to deliver the newspaper by herself?
Answer by addingup(3677) (Show Source): You can put this solution on YOUR website!
Let x = amount of time it takes the sister to complete route by herself
:
Sister = 1/x route per minute
Brother = 1/45 route per minute
Together = 1/20 route per minute
Put these together in an equation:
1/x + 1/45 = 1/20 multiply each term by 90x
90+2x = 4.5x
90 = 2.5x
x = 36
It takes the sister 36 minutes.
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