SOLUTION: Please help. Amy and Nancy can deliver papers together in 20 minutes. If it takes Nancy twice as long as Amy to deliver the papers by herself, how long would it take each girl t

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Question 980979: Please help.
Amy and Nancy can deliver papers together in 20 minutes. If it takes Nancy twice as long as Amy to deliver the papers by herself, how long would it take each girl to deliver the paper by herself?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +t+ = time in minutes for Amy to deliver papers
+2t+ = Nancy's time in minutes to deliver papers
----------------------
Amy's rate of delivering papers is:
[ All papers delivered ] / [ t minutes ]
Nancy's rate of delivering papers is:
[ All papers delivered ] / [ 2t minutes ]
----------------------------------
Add their rates of delivering papers to
get their rate working together
+1%2Ft+%2B+1%2F%282t%29+=+1%2F20+
Multiply both sides by +20t+
+20+%2B+10+=+t+
+t+=+30+
and
+2t+=+60+
----------------
Alone, Amy delivers the papers in 30 min
Alone Nancy delivers the paper in 1 hr
check:
+1%2Ft+%2B+1%2F%282t%29+=+1%2F20+
+1%2F30+%2B+1%2F60+=+1%2F20+
+2%2F60+%2B+1%2F60+=+3%2F60+
+3%2F60+=+3%2F60+
OK