Given that Easton went to the Live Oak County carnival. He paid $3 for every 15 tickets he bought. He spent a total of $21 on tickets.
We can determine the number of tickets Easton bought using direct proportion.
This can be seen below;
[tex]\begin{gathered} \text{ \$3 =15tickets} \\ \text{ \$21 = t tickets} \\ \text{This implies} \\ \frac{3}{15}=\frac{21}{t} \end{gathered}[/tex]Answer: Option D