Question

use the table for the next question the table represents a proportional relationship X and Y a 2 8 5 20 7 28 what is the value for k for the table above

Answer 1

From the table given,

The relationship between x and y is

$\begin{gathered} y\propto x \\ y=kx \end{gathered}$

Where x = 2 and y = 8,

Substitute for x and into the formula above

$\begin{gathered} y=kx \\ 8=k\times2 \\ 8=2k \\ \text{Divide both sides by 2} \\ \frac{8}{2}=\frac{2k}{k} \\ 4=k \\ k=4 \end{gathered}$

Where x = 5 and y = 20,

Substitute for x and y into the formula

$\begin{gathered} y=kx \\ 20=k\times5 \\ 20=5k \\ \text{Divide both sides by 5} \\ \frac{20}{5}=\frac{5k}{5} \\ 4=k \\ k=4 \end{gathered}$

Hence, the value of k for the table is 4