If it takes 4 men 6 hours to repair a road, how long will it take 7 men to do the job if they work at the same rate ?

So, there are 4 men working for 6 hours each, after the 6 hours, each man has worked 6 hours each, the total amount of "workhours" is 4 * 6, or 24 workhours, it took  24 workhours to do the whole job.

now, how long will it take for 7 men working at the same rate?,   24/7  <--- that many hours.

the division will give how long each man worked, and since it will be the same amount for each, that many hours it took for the whole job being done by the 7 of them.

What are you asking, I can help you if you give more context on what your asking.