Mathematics for IGCSE & O level - Proportion (Section 3 - No. 26)
If 'y' varies inversely as the square root of 'x' and y = 4 when x = 9, find y when x = 4.
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คำอธิบาย
y=k/√(x), and 4=k/√(9), or 4 = k/3. Therefore, k=12. When x = 4, y = 12/√(4) = 12/2 = 6