Question

4. A and B can do a certain job in 5 h, and A alone can do it in 8 h. How long will B take to do
the job alone​

Answer 1

Answer:

Time taken to do the job by (A+B) = 5hrs.

Time taken to do the job by A alone = 8hrs

Then, (A+B)'s 1 hour work = 1/5

and A's 1 hour work = 1/8

So, B's 1 hour work = {(A+B)'s 1 hr work} - {A's 1 hr work}

= 1/5-1/8

= 8/40 - 5/40

= 3/40

Hence, 40/3 will B alone to do the job.