ECZ 2024 · GCE Paper 1 — Sequences and Series
The sequence 20, 17, 14, ... is an arithmetic progression. Find the sum of the first 10 terms.
- A. -65
- B. 65
- C. 50
- D. 35
Verified working — step 1
Adding ten 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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