Answer:
The correct option is C. 9 houses could 18 men paint in 6 hours.
Step by step explanation:
Let the number of houses paint by 18 men in 6 hours be x.
One man can paint one house in 12 hours.
The part of house painted by a man in 1 hour is .
The part of house painted by a man in 6 hour is
The total number of men is 18. Therefore the number of houses painted by 18 men is
Therefore correct option is C. 9 houses could 18 men paint in 6 hours.