SOLUTION: It takes amy twice as longt to deliver papers ai it does nancy. How long would it take each girl to deliver the papers by herself if they can deliver the papers together in 40 min

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Question 187121This question is from textbook
: It takes amy twice as longt to deliver papers ai it does nancy. How long would it take each girl to deliver the papers by herself if they can deliver the papers together in 40 minutes. This question is from textbook

Found 2 solutions by solver91311, checkley77:
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


If A can do a job in x time periods, then A can do of the job in 1 time period. Likewise, if B can do the same job in y time periods, then B can do of the job in 1 time period.

So, working together, they can do



of the job in 1 time period.

Therefore, they can do the whole job in:



time periods.

Your problem is stated backwards, so you can say:



But you also know that because one of them works twice as fast as the other, so:



Solve for x to get the faster person's time, and then multiply that by 2 to get the slower person's time.

John

Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
x*2x/(x+2x)=40
2x^2/3x=40
2x^2=3x*40
2x^2=120x
2x^2-120x=0
2x(x-60)=0
2x=0
x=0/2
x=0 ans.
x-60=0
x=60 ans.
Proof:
60*120/(60+120)=40
7200/180=40
40=40