P and Q can finish a work in 10 days and 5 days, respectively. Q worked for 2 days and left the job. In how many days can P alone finish the remaining work?

Let the total work be W

Number of required for P to finish the work = 10 days

$$=$$>  Work done by P in 1 day = $$\frac{W}{10}$$

Number of required for Q to finish the work = 5 days

$$=$$> Work done by Q in 1 day = $$\frac{W}{5}$$

$$=$$> Work done by Q in 2 days = $$\frac{2W}{5}$$

Remaining work = $$\text{W}-\frac{2W}{5}$$ = $$\frac{3W}{5}$$

$$\therefore\ $$Number of days required for P to finish the remaining work = $$\frac{\frac{3W}{5}}{\frac{W}{10}}$$ = $$\frac{3W}{5}\times\frac{10}{W}$$ = 6 days

Hence, the correct answer is Option A