CAT 2019 Shift 1 Paper

Let one machine completes 1 unit of work per day.
Given, two machines can finish the job in 13 days
Therefore, the work of $2\times 1\times 13=26$ units.
Also, let on man completes $\mathit{m}$ units of work per day.
From the given condition:
$3\mathit{m}+8\times 1=2\left(8\mathit{m}+3\times 1\right)$
Or $\mathit{m}=\frac{2}{13}$ units
Let it require ' $\mathit{x}$ ' number of men to complete the work in 13 days.
Therefore, $\mathit{x}\mathit{m}\times 13=26$ units
Or $\mathit{x}=13$ men