Question:
Rakesh can do a piece of work in 20 days. How much work can he do in 4 days?
Solution:
It is given that Rakesh can do a piece of work in 20 days.
$\therefore$ Rakesh 's 1 day's work $=\frac{1}{20}$
$\therefore$ Rakesh's work for 4 days $=\frac{4}{20}=\frac{1}{5}$
Thus, he can do $\frac{1}{5}$ th of the work in 4 days.