Question

A can do a piece of work in 25 days and B can finish it in 20 days. They work together for 5 days, then A leaves. In how many days will B finish the work?

Answer 1

★ QUESTION :

A can do a piece of work in 25 days and B can finish it in 20 days. They work together for 5 days and then A leaves. In how many days will B finish the remaining work ?

GIVEN :

• Time taken by A to finish the work = 25 days.

• Time taken by B to finish the work = 20 days.

TO FIND :

• Time taken by B to cover the remaining work = ?

STEP-BY-STEP EXPLAINATION :

➠ Time taken by A to finish the work = 25 days

➠ Time taken by B to finish the work = 20 days

As Now, here we will have to find the time taken by B to cover the remaining work :

➠ A's 1 day work = 1/25

➠ B's 1 day work = 1/20

$➠ (A + B)'s \: 1 \: day's \: work = (\frac{1}{25} + \frac{1}{20} ) = \frac{9}{100}$

$➠ (A + B)'s \: 5 \: day's \: work = (5 \times \frac{9}{100}) = \frac{9}{20}$

$➠ Remaining \: work =( 1 \ - \frac{9}{20}) = \frac{11}{20}$

Now, 1/20 work done by B in 1 day

Hence 11/20 work will be done by B in :

$(\frac{11}{20} \times 20) \: days \: = 11 \: days$

Therefore, the remaining work is done by B in 11 days.