Answer:
4 hours
Explanation:
In 6 hours, J paints 1 room 
 
So, in 1 hour, J paints 1/6 th of the room 
 
Using similar logic, in 1 hour, T paints 1/12 th of the room. 
 
Working together in one hour, they paint (1/6+1/12) th =1/4 of the room. 
 
1/4 of the room is painted in 1 hour
So, 1 room is painted in 1 1/4=4 hours