(23 - 15 1/3) : (-5 1/9)

1. Convert mixed numbers to improper fractions: (23 - 46/3) : (-46/9).
2. Perform subtraction: ((69-46)/3) : (-46/9) = (23/3) : (-46/9).
3. Divide the fractions: (23/3) * (-9/46) = (23*(-9))/(3*46) = (1*(-3))/(1*2) = -3/2 = -1.5.