Children are $$\frac{3}{5}$$ of the adults: adults = 5 units, children = 3 units. The 3 units are 15 children.<br><br>[[model:questions/solutions/q3429.png]]<br><br>• 3 units → 15 children<br>• 1 unit → 15 ÷ 3 = 5<br>• Adults → 5 units = 25<br>• Passengers → 25 + 15 = 40<br><br>There are 40 passengers.<br>Check: children → $$\frac{3}{5}$$ of 25 = 15; 25 + 15 = 40. ✓