1. Stating the problem: The number of members increases from 60 to 75, and we need to find the percentage increase. 2. Calculate the increase in members: $75 - 60 = 15$. 3. Calculate the percentage increase: $$\frac{\text{increase}}{\text{original number}} \times 100 = \frac{15}{60} \times 100$$ 4. Simplify the fraction: $$\frac{15}{60} = \frac{1}{4}$$ 5. Calculate the percentage: $$\frac{1}{4} \times 100 = 25\%$$ Answer: The percentage increase in the number of members is 25%.