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Daily puzzle · 2026-10-18 · Arithmetic Sequences

Mathbound Daily Puzzle — 2026-10-18 — Arithmetic Sequences Solution

Level 2

Arithmetic sequence: first term 22, common difference 55. Sum of first 2020 terms?
  1. A.985
  2. B.1010
  3. C.40
  4. D.97
  5. E.990

Answer: E

Key idea: Sn=n2(2a+(n−1)d)S_n=\frac n2(2a+(n-1)d).

Set it up: Plug values.

Solution: 990990.

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Mathbound Daily Puzzle — 2026-10-18 — Arithmetic Sequences Solution