SOLUTION: If Tom can do a job in 2 hours and Jerry can do the same job in 3 hours, how long will it take them to do the job together? The answer is less than 1.5, however, you can't combi

Algebra ->  Equations -> SOLUTION: If Tom can do a job in 2 hours and Jerry can do the same job in 3 hours, how long will it take them to do the job together? The answer is less than 1.5, however, you can't combi      Log On


   

Question 763951: If Tom can do a job in 2 hours and Jerry can do the same job in 3 hours, how long will it take them to do the job together?
The answer is less than 1.5, however, you can't combine the times and average, would it make more sense to convert them into fractions?
Please help? Hate word problems, and it's been 36 years since I've taken an algebra course.
Found 2 solutions by josmiceli, solver91311:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
With work problems, you must add their
RATES of working to get their RATE of working together
( sorry for shouting )
Tom's rate:
( 1 job ) / ( 2 hrs )
Jerry's rate:
( 1 job ) / ( 3 hrs )
----------------
Let +t+ = the time in hrs for them
to finish the job working together
This rate is ( 1 job ) / ( t hrs )
-------------------------
+1%2F2+%2B+1%2F3+=+1%2Ft+
Multiply both sides by +6t+
+3t+%2B+2t+=+6+
+5t+=+6+
+t+=+1.2+ hrs
----------------
Every work problem is set up like this,
they will just be asking for different things

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.

So you could just do it in the formulatic way:

Or use the logic laid out above:

Whole job in 2 hours, then of the job in one hour. Likewise, for the other guy, of the job in one hour.

Then of the job in one hour, or the whole job in hours.

John

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