Adults are 5 equal units. Children are 3⁄5 of the adults = 3 units = 15.

Adults55555Children55515

Plain numbers are given; italic underlined numbers are worked out.

  1. Children = 3 units → 15
  2. 1 unit → 15 ÷ 3 = 5
  3. Adults = 5 units → 25
  4. Passengers = 25 + 15 = 40

The number of passengers is 40.

Check: children 3⁄5 of 25 = 15; 25 + 15 = 40. ✓