Answer:
4 hours
Step-by-step 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