Question

Determine the constant of proportionality from the following table.
$\begin{array}{cccccc}x& 3& 6& 15& 20& 30\\ y& 12& 24& 45& 60& 120\end{array}$

• A. $4$
• B. Both a and b are correct.
• C. $3$
• D. $x$ and $y$ are not in proportion.

Answer 1

The correct option is D $x$ and $y$ are not in proportion.

If $x$ and $y$ are in proportion, then $\frac{y}{k}$ (constant)
$\begin{array}{cccccc}x& 3& 6& 15& 20& 30\\ y& 12& 24& 45& 60& 120\\ \frac{y}{x}& 4& 4& 3& 3& 4\end{array}$
Since the value of $k$ is not the same in all cases, we can conclude that $x$ and $y$ are not in proportion.