Answer:
12 hours a day
Explanation:
To find this answer we have to multiply 9x24 to know how many total hours they need.
9x24 = 216
To find out how many hours are needed a day to complete this 6 days earlier, we have to subtract 24 - 6 = 18 days
Now all we need to do now is to find out what goes times against 18 and equals 216.
We can divided to find this ---> 216/18 = 12 hours
That would be 12
So, 12x18=216
The workers need to work 12 hours a day.
Hope this helped