A contractor undertakes to complete a road 360 m long in 120 days and

1.	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 employ so that the work may be completed in time ? (a) 20 (b) 30 (c) 15 (d) 45
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 \(\frac{120}{30\times60}\)m long road. Also, (30 + x) men in 60 days complete 240 m long road. \(\therefore\) 1 man in 1 day will complete \(\frac{240}{(30+X)\times60}\)m long road. \(\Rightarrow\) \(\frac{120}{30\times60}\) = \(\frac{240}{(30+X)\times60}\)m \(\Rightarrow\) \(\frac{1}{15}\) = \(\frac{4}{(30+X)}\) \(\Rightarrow\) 30 + x = 60 \(\Rightarrow\) x = 30 \(\therefore\) 30 more men have to be employed

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 employ so that the work may be completed in time ? (a) 20 (b) 30 (c) 15 (d) 45

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 \(\frac{120}{30\times60}\)m long road.

Also, (30 + x) men in 60 days complete 240 m long road.

\(\therefore\) 1 man in 1 day will complete \(\frac{240}{(30+X)\times60}\)m long road.

\(\Rightarrow\) \(\frac{120}{30\times60}\) = \(\frac{240}{(30+X)\times60}\)m \(\Rightarrow\) \(\frac{1}{15}\) = \(\frac{4}{(30+X)}\)

\(\Rightarrow\) 30 + x = 60 \(\Rightarrow\) x = 30

\(\therefore\) 30 more men have to be employed