The value of an avar controlling the $x$-coordinate of a ball is $18$ in frame $4$, and $30$ in frame $14$. The $x$-coordinate of the ball between those frames is determined by linear interpolation.
![Animation keyframes](https://ka-perseus-images.s3.amazonaws.com/5c170c3f8db9eaac189876d12871d91a5ef10edf.png)
**What is the value of the ball's $x$-coordinate in frame $7$?** [[☃ numeric-input 1]]