SOLUTION: BJ can overhaul a boat's diesel inboard engine in 20 hours. His apprentice takes 6 hours to do the same job. how long would it take them working together assuming no gain or loss i

Question 1025945: BJ can overhaul a boat's diesel inboard engine in 20 hours. His apprentice takes 6 hours to do the same job. how long would it take them working together assuming no gain or loss in efficiency
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
First of all, you have to imagine 2 people working
on an engine without getting in eachother's way.
It's not like painting a fence.
But as long as you can assume that, add their
rates of working to get their rate working together.
BJ's rate:
[ 1 engine overhauled ] / [ 20 hrs ]
Apprentice's rate:
[ 1 engine overhauled ] / [ 6 hrs ]
Let = their time in hrs working together
to overhaul engine
Rate working together:
[ 1 engine overhauled ] / [ t hrs ]
------------------------------

Multiply both sides by

Working together, it takes them 4 hrs and 8 min
check:

OK
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