math 31 calculus question. Need help!!!!

Question

A light airplane flies north at 250 km/hr. At the same time, another airplane starts from an airport 140 km north of the first airplane and is travelling east at 300 km/hr. What is the closest distance (to the nearest kilometer) that the two airplanes ever approach each other? Also, how much time does that take to happen?

Answer 1

Here is the URL to the Desmos graph referenced in the video.

https://www.desmos.com/calculator/5s7hvnpidk

Note that the function given for the distance between the two planes applies even if the north bound plane has flown past the airport that was originally 140 km due north.