Forty five (45) men do a job in 16 days. Six days after they started working, 30 more men joined them. How many days will they now take to complete the remaining work?

Correct option is D

The total work required to complete the job is:
Total work = 45 men × 16 days = 720 man-days
In the first 6 days, 45 men are working. The work done is:
Work done in 6 days = 45 men × 6 days = 270 man-days
Remaining work = Total work - Work done in 6 days
Remaining work = 720 man-days - 270 man-days = 450 man-days
Additional men join after 6 days:After 6 days, 30 more men join, so the total number of men now working = 45 + 30 = 75 men
The number of days required to finish the remaining work:
Days required = Remaining work / Number of men
Days required = 450 man-days / 75 men = 6 days
The remaining work will be completed in 6 days.