ECZ 2023 · GCE Paper 1 — Sequences and Series
An Arithmetic Progression is given as 1, 7, 13, ... Find the sum of the first fifteen terms.
- A. 555
- B. 645
- C. 5550
- D. 660
Verified working — step 1
Adding fifteen terms one by one would work, but the sum formula is faster: Sn = n2(2a + (n - 1)d).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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