Sunil can do a piece of work in 10 days and Nikhil alone can do it in 12 days. Nikhil works it for 3 days and then leaves. Sunil alone can finish the remaining work in - Sri Chaitanya Infinity Learn Best Online Courses for NCERT Solutions, CBSE, ICSE, JEE, NEET, Olympiad and Class 6 to 12

Work done by Sunil in 1 day $= \frac{100 %}{10} \Rightarrow 10 %$

Work done by Nikhil in 1 day $= \frac{100 %}{12} \Rightarrow \frac{25}{3} %$

Work done by Sunil in 3 days $= \frac{25}{3} \times 3 \Rightarrow 25 %$

$75 %$ of work done by Sunil $= 75 \times \frac{1}{10} = 7.5 d a y s$

Sunil's one day work = $\frac{1}{10}$

Nikhil's one day work = $\frac{1}{12}$

Nikhil's 3 days work = $\frac{3}{12} = \frac{1}{4}$

Remaining work ( $\frac{3}{4} t h$ ) can finish by Sunil in

$1 \to \frac{1}{10}$

$? \to \frac{3}{4} \Rightarrow 7.5 d a y s$