An engineer undertakes a project to build a road 10 km long in 60 days and employs 30 men for the purpose. After 20 days, he finds only 2 km of the road has been completed. Find the (approximate) number of extra men he must employ to finish the work in time. Choose the correct option:
A) 20
B) 15
C) 30
D) 45
E) 60
30 workers working already   Let x be the total men required to finish the task in next 40 days   2 km done hence remaining is 8 km   Also, work has to be completed in next 40 days (60 - 20 = 40)   We know that, proportion of men to distance is direct proportion   and, proportion of men to days is inverse proportion   Hence, X = (30 * 8 * 20) / (2 *40)   thus, X = 60   Thus, more men needed to finish the task = 60-30= 
<gadget id="calculator">60-30</gadget>
<output>30</output>
30   Answer : 30
<result>C</result>
An engineer undertakes a project to build a road 10 km long in 60 days and employs 30 men for the purpose. After 20 days, he finds only 2 km of the road has been completed. Find the (approximate) number of extra men he must employ to finish the work in time.