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

Step-by-step explanation:

A can do work in 8hr

So, work done by A in 1 hr = 1/8

B can do work in xhr

So, work done by B in 1 he = 1/x

A and B can do work in 5 hr work done by both A and B in 1hr = 1/5

1/8 + 1/x = 1/5

1/x = 1/5 - 1/8

1/x = 8-5/40

1/x = 3/40

Now cross multiply

3x = 40

x = 40/3

x = 13 1/3 hr

x = 13 hr 20 min ANS.

I HOPE THIS WILL HELP YOU :)