120 men working 9 hours a day can construct a road in 40 days. how long would it take to construct the same road if 150 men work 6 hours a day on it?

48 days

Explanation:

From the given information:

The total number of hours it took 120 men to work for 40 days is:

= 9 × 40

= 360 hours

Now; a single man will have to work for:

= 360 × 120 hours

= 43200 hours

However, for 150 men, the number of hours they will need to work will be:

= 43200 hours/150

= 288 hours

Provided it will take them 6 hours in a day to work;

Then, the number of days required to construct the same road is:

= 288/6

= 48 days