ECZ 2025 · O-Level Paper 1 — Sequences and Series
Given that 7, 11, 15, 19, … is an arithmetic progression, find: (a) the tenth term; (b) the sum of the first twelve terms.
- A. (a) 43 (b) 348
- B. (a) 47 (b) 396
- C. (a) 39 (b) 324
- D. (a) 43 (b) 290
Verified working — step 1
Identify a and d first; then each part is one formula: Tn = a + (n - 1)d for a term, Sn = n2(2a + (n - 1)d) for a sum.The full step-by-step working and final answer, plus the video lesson for this topic, 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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