Hi Nicole, I realise this is an old problem and you might have solved it yourself or have had it solved elsewhere but I have attempted this problem. My solution is as follows. Room 1 not assigned, room 2 =G, room 3 = F, room 4 = not assigned, room 5 assigned to B AND C, room 6 not assigned, room 7 = A, room 8 = H AND I, room 9 D AND E, room 10 = J. I didn't see a constraint that says unoccupied and double occupancy are banned and SOLVER gives me the above. I would love to see the correct answer IN CASE THE ABOVE IS RUBBISH! I will share my Excel fille too if you want.