1. **State the problem:** We need to find what percentage of the tickets sold were child tickets. 2. **Identify the given values:** Total tickets sold = 40, Child tickets sold = 24. 3. **Formula for percentage:** $$\text{Percentage} = \left(\frac{\text{Part}}{\text{Whole}}\right) \times 100$$ 4. **Apply the formula:** $$\text{Percentage of child tickets} = \left(\frac{24}{40}\right) \times 100$$ 5. **Simplify the fraction:** $$\frac{24}{40} = \frac{\cancel{8} \times 3}{\cancel{8} \times 5} = \frac{3}{5}$$ 6. **Calculate the percentage:** $$\frac{3}{5} \times 100 = 3 \times \frac{100}{5} = 3 \times 20 = 60$$ 7. **Final answer:** 60% of the tickets were child tickets.