Question

A contractor undertakes to complete a road 360 m long in 120 days and employs 30 men for the work. After 60 days he finds that only 120 m length
of the road has been made . How many more men should he emply so that the work many be complete in time ?

• A. 20
• B. 30
• C. 15
• D. 45

Answer 1

Answer: (B)

30

Let the number of extra men employed be x 30 men in 60 days complete 120 m long road
1 man in 1 day will complete $\frac{120}{30\times 60}$ m long road Also (30 + x) men in 60 days complete 240 m long road
$\therefore$ 1 man in 1 day will complete $\frac{240}{(30+x)\times 60}m$ long road $\Rightarrow \frac{120}{30\times 60}=\frac{240}{(30+x)\times 60}\Rightarrow \frac{1}{15}=\frac{4}{(30+x)}$
$\Rightarrow$ 30 + x = 60 $\Rightarrow$ x = 30 $\therefore$ 30 more men have to be employed