posted by Songthan .
A commercial freight carrier is flying at a constant speed of 400mi/h and is traveling 4 mi east for every 3 mi north. A private plane is observed to be 210 mi due east to the commercial carrier, traveling 12 mi north for every for 5 mi west.
a.If it is known that the two planes are on collision course, how fast is the private plane flying ?
b. When will the collision take place if it is not averted?