1. The problem statement, all variables and given/known data Two rooms, each a cube 3.8 m on a side, share a 12 cm thick brick wall. Because of a number of 100 W light-bulbs in one room, the air is at 27°C, while in the other room it is at 10°C. How many of the 100 W light-bulbs are needed to maintain the temperature difference across the wall? (Round your answer up to the nearest integer.) 2. Relevant equations Q/t=kA(t1-t2)/l 3. The attempt at a solution This looks so easy and I attempt to solve it and I get it wrong. I used Q/t=kA(t1-t2)/l =(0.84J/s*m*C)(14.44m2)(27C-17C) / (0.12m) =1718.36 then divide by 100 and it equals 17.1836=17 Do you have any ideas as to what I'm not comprehending because I'm sure this has to be the correct number of bulbs.