Explanation:
x = number of deluxe staterooms on Pacific.
deluxe staterooms on Caribbean = x + 16
deluxe staterooms on Mediterranean = 4x - 28
1176 = x + (x + 16) + (4x - 28) = 6x - 12
1188 = 6x
x = 1188/6 = 198
so,
Pacific has 198 luxury staterooms.
Caribbean has 198 + 16 = 214 luxury staterooms.
Mediterranean has 4×198 - 28 = 792 - 28 = 764 luxury staterooms.