Two planes leave Toronto and New York City at the same time each day going to the other city on the same path. One plane travels at 550 km/h and the other at 600 km/h. Assuming the planes are travelling at the same height, how far apart are they one hour before they meet?
Since the two planes are traveling towards each other on the same path, their combined speed is 550 km/h + 600 km/h = <<550+600=1150>>1150 km/h.
In one hour, they will cover a distance of 1150 km/h * 1 h = <<1150*1=1150>>1150 km. Answer: \boxed{1150}.