LIC AAO 22 Mar 2015 Paper

Let the number of men who left be x.
Part of work done by 20 men
in 5 days = $\frac{5}{16}$
∴Remaining work = 1 - $\frac{5}{16}$ = $\frac{11}{6}$
According to the question
$\frac{{\mathit{M}}_1{\mathit{D}}_1}{{\mathit{W}}_1}$ = $\frac{{\mathit{M}}_2{\mathit{D}}_2}{{\mathit{W}}_2}$
⇒ $\frac{20\times 16}{1}$ = $\frac{\left(20-\mathit{x}\right)\times 55}{\frac{11}{6}\times 3}$
⇒ 20 × 16 = $\frac{\left(20-\mathit{x}\right)\times 55\times 16}{11\times 3}$
⇒ 20 × 3 = (20 - x) × 5
⇒ 60 = 100 - 5x
⇒ 5x = 100 - 60 = 40
⇒ x = $\frac{40}{5}$ = 8