Assuming they can work in parallel, the answer should be 5. 5 men produce 1 hole per hour in the first example. At that rate, they produce 5 holes in 5 hours. The same 5 men, working at one hole per hour, should be able to produce 100 holes in 100 hours (assuming they don't need sleep, etc.)
It takes 3 x 6 = 18 man hours to dig 12 holes. Therefore it takes 18/12 = 1.5 man hours to dig 1 hole. To dig 9 holes takes 9 x 1.5 man hours = 13.5 man hours If 2 men are working then they take 13.5/2 = 6.75 hours or 6 hours 45 minutes.
two man-hours. limited only by the space available for diggers per hole.
You cannot dig half a hole. It may be only half as big, but it is still a hole. So the answer is a moment. This is an old, old riddle/joke.
Holes don't fill things up, they empty it
300/28 11 it takes 11 hours
It takes 3 x 6 = 18 man hours to dig 12 holes. Therefore it takes 18/12 = 1.5 man hours to dig 1 hole. To dig 9 holes takes 9 x 1.5 man hours = 13.5 man hours If 2 men are working then they take 13.5/2 = 6.75 hours or 6 hours 45 minutes.
How long it takes for you to get there.
it takes about 9 hours
it takes 11 hours
It takes 6 hours driving
It takes 24.7 hours.
It takes 3 hours.
Open Heart takes 6 hours
it takes 24 hours
It takes about 7-8 hours.
It takes about 4 hours.
It takes around 8 Hours!