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Zorluk: KolayDirect, Inverse, Joint and Partial Variation

The variable yy varies inversely as xx. If y=6y = 6 when x=4x = 4, what is the value of yy when x=8x = 8?

  1. 3Cevap
  2. B
    12
  3. C
    16
  4. D
    48

Cevap

The value of yy when x=8x = 8 is 3.
Since yy varies inversely as xx, the formula connecting them is y=kxy = \frac{k}{x}. Substituting y=6y = 6 when x=4x = 4 gives 6=k46 = \frac{k}{4}, which yields k=24k = 24. Using this constant, when x=8x = 8, y=248=3y = \frac{24}{8} = 3.

Adım Adım Çözüm

1
Write the relationship for inverse variation.
y=kxy = \frac{k}{x}
Inverse variation means yy is inversely proportional to xx, where kk is the constant of variation.
2
Substitute given values y=6y = 6 and x=4x = 4 to solve for kk.
6=k4    k=6×4=246 = \frac{k}{4} \implies k = 6 \times 4 = 24
To complete the equation of variation, the constant kk must be determined.
3
Substitute k=24k = 24 and x=8x = 8 into the variation equation to find yy.
y=248=3y = \frac{24}{8} = 3
Evaluating the relationship at x=8x = 8 gives the requested value.

Anahtar Kavram

Inverse Variation
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