linear equation

Question

A train travels east from Chicago at 6 pm at 45 mph (EST). A train travels west from Cleveland
at 35 mph at 7 pm (EST). If the cities are 285 miles apart and the trains are barreling toward
each other on a collision path, at what time will they collide?

Answer 1

45 + 35 = 80 (Every hour they're both moving, they're getting 80 miles closer)

285 - 45 = 240 (That first hour only Chicago train moves)

240 / 80 = 3 (three hours pass after both move)

7 + 3 = 10 (They're both moving at 7 pm. three hours past that is 10 pm)