Question

The value of y is directly proportional to the value x. If x = 5 when y = 12 find x when y = 30.

Answer 1

x=12.5

Explanation

Step 1

the proportion must be the same, then

Let

x1 represents the value for x when y= 30

$\begin{gathered} \frac{x}{y}=\frac{5}{12}=\frac{x_1}{30} \\ \text{then, we have} \\ \frac{5}{12}=\frac{x_1}{30} \end{gathered}$

Step 2

solve for x

$\begin{gathered} \frac{5}{12}=\frac{x_1}{30} \\ 30\cdot5=12\cdot x_1 \\ x_1=\frac{30\cdot5}{12} \\ x_1=\frac{150}{12} \\ x_{}=12.5 \end{gathered}$

I hope this helps you