SOLUTION: John can complete a job alone in 2 hours, and it takes Tim 3 hours to do the same job alone, how long would it take them if they work together?

Algebra ->  Rate-of-work-word-problems -> SOLUTION: John can complete a job alone in 2 hours, and it takes Tim 3 hours to do the same job alone, how long would it take them if they work together?      Log On


   

Question 662477: John can complete a job alone in 2 hours, and it takes Tim 3 hours to do the same job alone, how long would it take them if they work together?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Add their rates of working
( 1 job done ) / ( John's time to do it ) + ( 1 job done ) / ( Tim's time to do it )
= ( i job done ) / ( time with both working )
Let +t+ = time to do job with both working
+1%2F2+%2B+1%2F3+=+1%2Ft+
Multiply both sides by +6t+
+3t+%2B+2t+=+6+
+5t+=+6+
+t+=+6%2F5+
It will take them 1 + 1/5 hours, or
+1+%2B+60%2F5+ = 1 hour and 12 minutes working together