Question

The variables x and y vary inversely, and y = 8 when x = 3. Find the equation of inverse variation between x and y.

• A. xy =24
• B. y = 24 x
• C. x = 24 y
• D. xy = 12

Answer 1

The correct option is A

xy =24

Since x and y vary inversely, we have $y=\frac{a}{x}$ for some constant of proportionality a.

Given y = 8 when x = 3.

Thus $8=\frac{a}{3}\Rightarrow a=24$.

Substituting for a in $y=\frac{a}{x}$, we have $y=\frac{24}{x}\Rightarrow xy=24$.