Question

Difficulty: EasyDirect, Inverse, Joint and Partial Variation

If yy varies inversely as xx, and y=8y = 8 when x=3x = 3, what is the value of yy when x=6x = 6?

  1. 4Answer
  2. B
    16
  3. C
    24
  4. D
    2

Answer

4
For inverse variation, y=kxy = \frac{k}{x}. Given y=8y = 8 when x=3x = 3, the constant of variation k=8×3=24k = 8 \times 3 = 24. Substituting x=6x = 6 gives y=246=4y = \frac{24}{6} = 4.

Step-by-Step Solution

1
Set up the equation for inverse variation
y=kxy = \frac{k}{x}
Inverse variation means yy is inversely proportional to xx with constant kk.
2
Solve for the variation constant kk using y=8y = 8 and x=3x = 3
k=8×3=24k = 8 \times 3 = 24
Multiply both sides of the equation by xx.
3
Calculate yy when x=6x = 6
y=246=4y = \frac{24}{6} = 4
Substitute the constant k=24k = 24 and x=6x = 6 into the inverse variation equation.

Key Concept

Inverse Variation
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