There is a hill which has parallel train tracks on it$.$ The tracks run for $66$ miles up the hillside. One train is at the top of the hill, moving down at $19$mi$/$h$19$mi$/$h$.$ Another train is on the other set of tracks, moving up the hill at $10$mi$/$h$10$mi$/$h$.$ The first train accelerates at $10$mi$/$h$210$mi$/$h$2$as it goes down the hill, but the second train does not accelerate or decelerate. How far up the hill are they when they pass?

Select one:

a$.$

$2$mi$2$mi

b$.$

$31$mi$31$mi

c$.$

$15$mi$15$mi

d$.$

$2910$mi