ECZ 2019 · GCE Paper 1 — Variation
y varies directly as x and inversely as the square of z, with constant k = 5 (so y = 5xz²). Find z when x = 9 and y = 5.
- A. z = 3 only
- B. z = 9 or −9
- C. z = 3 or −3
- D. z = ±√5
Verified working — step 1
5 = 5 × 9z² gives z² = 455= 9, so z = ±√9 = …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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