Question

20 men were engaged to complete job in 10 days ,but it was half finished in 6days. How many additional men required to finish job in time?

Answer 1

$20 \: men \: required \: \\ total \: days = 6 + 6 = 12 \: days \\ half \: finished = 10 - 6 = 4days \\ remaining \: 4 \: days \\ so \: if \: number \: of \: men \: changed \\ \: assume \: a \: \: it \: \: will \: divide \: = \frac{1}{a} \\ so \\ 6a = 4 \\ a = \frac{4}{6} \\ a = \frac{2}{3} \\ so \: \: the \: number \: of \: men \: increased \\ \frac{1}{a} \times 20 = \frac{3}{2} \\ 3 \times 20 \div 2 \\ \frac{60}{2} \\ = 30 \\ additional \: men \: required \\ = 30 - 20 = 10 \\ ans \: is \: 10men$