ECZ 2024 · GCE Paper 2 · Question 6 — Sequences and Series

Question from ECZ 2024 · GCE Paper 2 · Question 6

(a) The first three terms of a geometric progression are 3w - 2, 3w + 6 and 3w + 30. Find the

(a(i)) value of w,[3]

Verified working — step 1

Consecutive GP terms share a ratio, so (2nd)2 = (1st)(3rd):

(a(ii)) nth term,[2]

Verified working — step 1

With w = 2 the terms are 4, 12, 36, ... so a = 4 and r = 124 = …

(a(iii)) sum of the first 4 terms.[2]

Verified working — step 1

Sn = arn - 1r - 1 with a = 4, r = 3:

(b) Simplify 10am2 n2 ÷ 5a32m2 n2.[2]

Verified working — step 1

Multiply by the reciprocal:

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Original examination question © Examinations Council of Zambia. Worked solution and commentary © G12 Titan — not to be reproduced without permission.

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