The 3 cabins together hold 3 × the average. Let cabin 3 be 1 unit: cabin 1 = 1 unit + 50, cabin 2 = 2 units.<br><br>[[model:questions/solutions/q4696.png]]<br><br>• Total → 3 × 190 = 570<br>• 1 + 1 + 2 = 4 units, plus 50 → 570<br>• 4 units → 570 − 50 = 520<br>• 1 unit (cabin 3) → 520 ÷ 4 = 130<br>• Cabin 2 → 2 × 130 = 260<br><br>There are 260 passengers in the second cabin.<br>Check: 130 (3rd) + 180 (1st) + 260 (2nd) = 570; 570 ÷ 3 = 190. ✓