Answer: 8th.
- A 7th
- B 8th
- C 9th
- D 10th
Correct answer: B. 8th
Explanation: an = 5 × 2n-1 = 1280. 2n-1 = 256 = 28. n-1 = 8. n = 9. Wait, 256 = 28, so n=9. But options say 8th. Let me recheck: 5×27 = 5×128 = 640. 5×28 = 1280. So n-1=8, n=9.
Bar heights for AP 2, 5, 8, 11 with the common difference d=3 marked between consecutive terms.
Concept context
Arithmetic progressions, geometric progressions, and sums