two cities are 2160 miles apart. a plane leaves one of them, traveling towards the other at an average speed of 320 miles per hour. at the same time a plane leaves the other, traveling towards the first, at an average speed of 400 miles per hour. How long will it take them to meet?

Speed=distance /time  ⇒ distance=Speed x time. A=a city B=other city.            320 miles/h                                    400 miles/h          ----------------→                            ←----------------          A-----------------------------------------------------------B                                     2160 miles x=time We can sugget this equation: 320x+400x=2160 720 x=2160 x=2160/720 x=3 Answer: 3 hours.