1. **State the problem:** We have 50 ninth graders and 72 tenth graders on the honor roll last year. This year, the number of ninth graders decreased by 24% and the number of tenth graders decreased by 25%. We need to find the percentage decrease in the total number of students on the honor roll. 2. **Write down the initial numbers:** - Ninth graders last year: $50$ - Tenth graders last year: $72$ 3. **Calculate the number of students this year:** - Ninth graders this year: $50 - 0.24 \times 50 = 50 \times (1 - 0.24) = 50 \times 0.76 = 38$ - Tenth graders this year: $72 - 0.25 \times 72 = 72 \times (1 - 0.25) = 72 \times 0.75 = 54$ 4. **Calculate total students last year and this year:** - Total last year: $50 + 72 = 122$ - Total this year: $38 + 54 = 92$ 5. **Calculate the decrease in total students:** $$\text{Decrease} = 122 - 92 = 30$$ 6. **Calculate the percentage decrease:** $$\text{Percentage decrease} = \frac{30}{122} \times 100 = \frac{30}{122} \times 100 \approx 24.59\%$$ 7. **Round to the nearest tenth:** $$24.6\%$$ **Final answer:** The total number of students on the honor roll decreased by approximately $24.6\%$ this year.