UP Police Constable Exam Model Paper 5

Given
Work done by all in one day $=\mathit{A}+\mathit{B}+\mathit{C}=\frac{1}{2}$
Work done by $\mathit{A}$ in one day $=\frac{1}{4}$
Work done by $\mathit{C}$ in one day $=\frac{1}{6}$
Calculation:
Work done by $\mathit{B}$ in one day $=\frac{1}{2}-\left[\frac{1}{4}+\frac{1}{6}\right]$
$=\frac{1}{2}-\frac{10}{24}$
$=\frac{\left(24-20\right)}{48}$
$=\frac{4}{48}$
$=\frac{1}{12}$
So, B takes 12 days to accomplish the task.