Question

X varies directly as the cube of Y. If X = 3 when Y = 2, then find the constant of variation.

• A. 0.375
• B. 0.25
• C. 0.2
• D. 0.5

Answer 1

The correct option is A 0.375

Let the constant of variation be k.
Given, X varies directly as the cube of Y.
$\Rightarrow X\propto Y^3$
$\Rightarrow X=k{Y}^3$
Given, at X = 3, Y = 2.
So, $k=\frac{X}{Y^3}=\frac{3}{2^3}=\frac{3}{8}=0.375$