Buses go past my stop throughout the day. I arrive at the stop at a completely random time during the day. What is the expected length of time I will have to wait for a bus, if the schedule stops are the following a. Exactly 20 minutes apart. b. Exactly 20 minutes past the hour and 40 minutes past the hour (e.g. ~8:20, 8:40, 9:20, 9:40, etc.) c. Exactly at the top of the hour, 10 minutes past the hour, and 30 minutes past the hours (e.g. ~8:00, 8:10, 8:30, 9:00, 9:10, etc.)