SOLUTION: Rob can deliver papers 4 times as fast as his younger brother. If they work together, it takes them 2 hours. How long would it take each to deliver the papers alone?

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Question 518777: Rob can deliver papers 4 times as fast as his younger brother. If they work together, it takes them 2 hours. How long would it take each to deliver the papers alone?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Call delivering the papers 1 job
Let +t+ = Rob's time to deliver the papers in hours
+4t+ = younger brother's time
Add their rates to get rate working together
+1%2Ft+%2B+1%2F%284t%29+=+1%2F2+
Multiply both sides by 4t
+4+%2B+1+=+2t+
+2t+=+5+
+t+=+5%2F2+
+4t+=+10+
Rob's time working alone is 2.5 hrs
Brother's time working alone is 10 hrs