Answer:
8 Hours
Explanation:
Let the the length of the road x
It takes 4 men 6 hours to repair a road and they work at the same rate.
So, each one will repair 0.25x
And the rate to repair the road will be 6 hour per 0.25x.
rate =

Now, if 3 men will do the job
each one of them will repair (1/3) x with the same previous rate
∴

So, The 3 men will do the job at 8 hours.