Question

The value of y varies directly with x. If x = 6, when y = 72. What is the value of x when y = 10812922/3

Answer 1

Given that y varies directly as x.

y = x

Introduce a constant k:

y = kx

x = 6, when y = 72.

We have:

72 = 6k

Solve for k:

Divide both sides by 6

$\begin{gathered} \frac{72}{6}=\frac{6k}{6} \\ \\ 12\text{ = k} \end{gathered}$

k = 12.

To find the value of x when y = 108:

y = kx

Substitute y for 108 and k for 12:

108 = 12x

Solve for x:

Divide both sides by 12:

$\begin{gathered} \frac{108}{12}=\frac{12x}{12} \\ \\ 9\text{ = x} \end{gathered}$

Therefore, x = 9 when y = 108.

ANSWER:

9