9. rise to the challenge problem 2: john is riding on a bus traveling at an average speed of 2.0 x
10 m/s. twenty minutes after john starts his bus ride, john's mom realizes that he left his wallet
in her car. she chases the bus at an average speed of 27 m/s. how long does it take john's
mom to reach the bus? assume she started the chase at the same place john started his bus
ride. (hint: make a d vs. t graph for this situation and find the equation for each line.)