ECZ 2018 · GCE Paper 1 — Variation
Two variables x and y have corresponding values shown in the table: when x = 2, y = 20; when x = 3, y = 40; when x = a, y = 104. Given that y varies directly as (x² + 1), find the constant of variation, k.
- A. 4
- B. 5
- C. 20
- D. 14
Verified working — step 1
Direct variation means y = k(x² + 1). Substitute the pair (2, 20): 20 = k(4 + 1) = 5k, so k = 4. (Check with (3, 40): 4 × (9 + 1) = …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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