A lift has the capacity of 18 adults or 30 children. How many children can board the lift with 12 adults?

1. **Identify the Goal:** We need to fill the remaining space in the lift with children.\n\n2. **Analyze the Gap (Residual Capacity):** \n - The lift can hold 18 Adults.\n - There are already 12 Adults inside.\n - The empty space is equivalent to $18 - 12 = 6$ Adults. [16]\n\n3. **Apply Equivalence and Scaling:**\n - We know the full capacity is 18 Adults = 30 Children. [1]\n - We need to find the equivalent of 6 Adults in terms of children.\n - Observe the relationship: 6 Adults is exactly one-third of 18 Adults ($18 \\div 3 = 6$).\n - Therefore, the number of children required must also be one-third of the total children capacity. [47]\n\n4. **Final Calculation:**\n - One-third of 30 Children = $30 \\div 3 = 10$ Children.\n - This uses the 'Direct Proportionality' logic seen in PYQs where values scale linearly. [35]\n\n5. **Conclusion:** 10 Children can board the lift.