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
WIL WIII be each person's share?
the job alone?​

Answer 1

Answer:

B will need 13 hours and 20 minutes.

Explanation- In order to complete 100% of work alone, A needs 8h time. So in 5 hours(300 minutes), he will complete 5/8 portion of total work i.e. 62.5% of total work. It means that in 5 hrs, B is doing 37.5% (100–62.5) of total work.

Thus in order to complete 100% of work alone, B will require (300/37.5)*100 minutes, which means a total of 800 minutes.

Thus B will need 13 hours 20 minutes to complete the same work all alone.

Peace.

Answer 2

PLEASE MARK IT AS BRAINLIEST AND FOLLOW ME

Answer:

A and B , both worked in time = 5 hours

A alone do the work in time = 8 hour

B alone do the work in time = x hour

$\frac{1}{a} + \frac{1}{b} = \ \frac{1}{a + b}$

$\frac{1}{8} + \frac{1}{b} = \frac{1}{5}$

$\frac{1}{b} = \frac{1}{5} - \frac{1}{8}$

$\frac{1}{b} = \frac{3}{40}$

$b = \frac{40}{3}$

$b = 13.3$

$therefore \: b \: takes \: 13.3 \: hours \: \: to \: complete \: the \: work \: alone$

Therefore b takes 13 hours and 20 mins to complete the work alone .