Question

if y varies directly as x, and y is 6 when x is 72, what is the value of y when x is 8? a. 1/9 b. 2/3 c. 54 d. 96

Answer 1

The value of y when x is 8 is b. 2/3

Answer 2

Answer:

The correct option is b.

Step-by-step explanation:

It is given that y varies directly as x.

$y\propto x$

$y=kx$

It is given that y is 6 when x is 72.

$6=k\times 72$

Divide both sides by 72.

$\frac{1}{12}=k$

The constant of proportionality is $\frac{1}{12}$.

$k=\frac{y}{x}$

$\frac{1}{12}=\frac{y}{8}$

$\frac{1}{12}\times 8=y$

$\frac{2}{3}=y$

The value of y is $\frac{2}{3}$. The correct option is b.