Answer:
• k=50/13
,• y=69.231 (to the nearest 1000th)
Explanation:
If y varies directly as x, the equation of variation is:
[tex]y=kx,\text{ k=variation constant}[/tex]When x=13 and y=50
[tex]\begin{gathered} 50=13k \\ k=\frac{50}{13} \end{gathered}[/tex]Substituting k into the equation above, we have:
[tex]y=\frac{50}{13}x[/tex]Therefore, when x=18
[tex]\begin{gathered} y=\frac{50}{13}\times18 \\ y\approx69.231 \end{gathered}[/tex]