Question

24 men can complete a work in 20 days. How many more men are required to complete the work in 12 days?

• A. 40
• B. 12
• C. 16
• D. 18

Answer 1

The correct option is C 16

Method 1: Using man-days

Amount of work in terms of man days $=24\times 20=480$ man days

So, number of men required to complete the work in 12 days $=\frac{480}{12}=40$ men.

16 more men are required. Hence option (c)

Method 2: Using constant product rule

Decrease in number of days $=\frac{1}{\left(\frac{20}{8}\right)}=\frac{1}{2.5}$

Increase in number of men $=\frac{1}{1.5}=$ 16 men to finish the same work.