Question

Sashi can do a piece of work in 25 days and rishi can do it in 20 days. they work for 5 days and then sashi goes away. in how many ;more days will rishi finish the work?

Answer 1

sashi's work per day =1/25
rishi's work per day =1/20

in 5 days, they will complete 5/25+5/20 of the job

=9/20
rest of the job has to be done by rishi alone and will take 1- 9/20 more days
=11 days.

Answer 2

Answer: Rishi would take 11 more days to finish the work.

Step-by-step explanation:

Since  we have given that

Number of days Sashi takes to complete a piece of work = 25 days

Number of days Rishi takes to complete a piece of work = 20 days

Number of work they work together = 5 days

Work done by Sashi in 5 days = $\dfrac{5}{25}=\dfrac{1}{5}$

Work done by Rishi in 5 days = $\dfrac{5}{20}=\dfrac{1}{4}$

So, Total work done by both of them is given by

$\dfrac{1}{5}+\dfrac{1}{4}\\\\=\dfrac{9}{20}$

Remaining work would be

$1-\dfrac{9}{20}\\\\=\dfrac{11}{20}$

Sashi goes away.So, remaining work is done by Rishi alone.

Number of days he takes to complete the remaining work is given by

$\dfrac{20}{\dfrac{20}{11}}\\\\=11\ days$

So, Rishi would take 11 more days to finish the work.