Question 422925
You set the problem up correctly.  Now all you have to do is solve for T, the number of two bedroom apartments.
Use the 1st equation to get an expression for B, then substitute into the 2nd equation:
B = 12 - T
360(12-T) + 450T = 4950 -> 4320 + 90T = 4950 -> T = (4950-4320)/90 = 7.
So the number of two bedroom apartments = 7.