Answer: 59.
- A 57
- B 58
- C 59
- D 61
Correct answer: C. 59
Explanation: aₙ = Sₙ − Sₙ₋₁ = 6n − 1. So a₁₀ = 60 − 1 = 59.
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