Question

6. A can do a piece of work in 4 hours and B in 12 hours. After B has worked for 4 hours, he is joined
by A. How long will A and B take to complete it?​

Answer 1

Answer:

After B has worked for 4 hours, he will have completed 1/3 (4/12 hours) of the work, leaving 2/3 of the work remaining.

A can finish 1/4 of the work in 1 hour while B can finish 1/12 of the work in 1 hour. So every hour they can finish 1/4 + 1/12 of the work or 4/12 or 1/3 of the work. Working together, they will require 2 hours to finish the remaining 2/3 of the work.

Step-by-step explanation:

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