Answer to the extra credit question on a fourth grade math pop quiz

Extra Credit: Two trains are traveling towards each other on the same track. The first train is accelerates at a rate of 10 miles per hour per minute, the second train accelerates at a rate of 15 miles per hour per minute. If the trains begin 68 miles apart, how long will it take the trains to collide?

[Handwritten] One day I’ll multiply 13 by 13 and get 171. One day I’ll look up into the sky and see a color with no name. One day I’ll step off the curb and there’ll be nothing there to catch me. One day someone will say my name and I won’t recognize it (I shall only answer to the name Eleutheria). One day straight lines will raise their hands and admit defeat. One day I’ll look in the mirror and see parts, not a whole. One day I’ll walk out of this classroom and forget I was ever in it.