Question

7 A and B, working together can complete a
job in 3 hours. If A alone can do the job in
7 hours, in how much time can B alone
finish the job?​

Answer 1

Answer:

B alone can complete the work  in 7/4 hours.

Step-by-step explanation:

A and B can complete the work in 3 hours and   A alone can do the job  in 7 hours.

We have to find that , in how much time can B alone finish the job.

Solution

A alone can  do  the work in 7 hours.

Then Let x be the time taken by B to complete the work.

Then,

1/x + 1/7 = 1/3

1/x = 1/3-1/7

Here , LCM of 3 and 7 is 21

∴ 1/x = 4/7

∵ 1/x = 4/7

x = 7/4 hours.