SOLUTION: A can do a certain job in 4 hrs, B can do the job in 6 hrs, and C can do the job in 8 hrs. How long will it take to do the job if A and B work 1 hr and B and C finish the job?

Question 964654: A can do a certain job in 4 hrs, B can do the job in 6 hrs, and C can do the job in 8 hrs. How long will it take to do the job if A and B work 1 hr and B and C finish the job?
Answer by josgarithmetic(39623) (Show Source): You can put this solution on YOUR website!
The rate of agents working at the same time is the sum of their rates.

Let t be the time for B and C to finish the job, AFTER A and B worked for one hour.

This is two expressions of job portions, summed. One for 1 hour by A and B, the other for unknown time by B and C.

Solve for t.
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