If 6 men take 9 days to complete a work, how many men can complete the work in 3 days?

A. 2 men
B. 12 men
C. 9 men
D. 18 men

For the work to be completed in 9 days,
6 men are required. Time and men are inversely proportional. For the work to be completed in 3 days,
6*9/3 = 18 men are required