A. 24
B. 22
C. 23
D. 25
🧠 Explanation:
The sequence 20, 25, 30, …, 140 has 25 terms (first term 20, common difference 5, last term 140; $n = frac{140-20}{5}+1 = 25$). Studying this highlights arithmetic sequences, a key topic in mathematics. It ensures accurate counting, with implications for pattern analysis in math or finance.
