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