RRB Group D 17-Sep-2018 Shift 1 Solved Paper

Ratio of days required by $\mathit{A}$ and $\mathit{B}$ to complete work $=3:5.$
No. of day they require to complete $=5\frac{5}{8}=\frac{45}{8}$ days
Let the efficiency of $\mathit{A}$ and $\mathit{B}$ are $\frac{1}{3\mathit{x}}$ and
$\frac{1}{5\mathit{x}}$ respectively.
$\Rightarrow$ Sum of their efficiency
$=\frac{1}{3\mathit{x}}+\frac{1}{5\mathit{x}}=\frac{8\mathit{x}}{15{\mathit{x}}^2}$
$\Rightarrow \frac{8}{15\mathit{x}}=\frac{8}{45}\Rightarrow \mathit{x}=3$
$\therefore$ A will complete the work in $3\times 3=9$ days