80 men can construct a small footpath in 100 days. How many more men should be employed if the job is to be finished in 25 days?

Correct option is D

Given:
80 men can construct a footpath in 100 days. Work has to be finished in 25 days.
Formula Used:
Work = Men × Days
​$$\text{Required Men} = \dfrac{\text{Original Men} \times \text{Original Days}}{\text{Target Days}}$$​​
Solution:
Total work = 80 × 100 = 8000 man-days
Work must be done in 25 days 
 Required men = $$\frac{8000}{ 25}$$​ = 320
Additional men needed = 320 − 80 = 240