ECZ 2020 · O-Level Paper 1 — Sequences and Series
For the sequence 7, 11, 15, 19, ..., find the sum of the first 16 terms.
- A. 592
- B. 616
- C. 1184
- D. 296
Verified working — step 1
Sₙ = n2[2a + (n - 1)d]. S₁₆ = 162[2×7 + 15×4] = 8[14 + 60] = 8×74 = …The full step-by-step working and final answer are included with Premium — checked against ECZ marking standards.
Original examination question © Examinations Council of Zambia. Worked solution and commentary © G12 Titan — not to be reproduced without permission.
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