B ) Midterm , 2005 ) Suppose a free bus operates between the STU Burnaby campus and the Downtown campus . There are two buses per day . The departure...

B ) Midterm , 2005 ) Suppose a free bus operates between the STU Burnaby campus and theDowntown campus . There are two buses per day . The departure time of the bus is randomThe first bus departs at 9 :15 9:30 or 9:45 . The second bus departs at 10:10 10:30 or 10:40The departure times of the two buses are independent of one another , and have the followingprobability distribution :Bus I Departure Time9:15 am9:30at9:45amProbability16IN1 13Bus 2 Departure Tim10 :10 am10:30 am10:40 amProbabilityDO121/3a ) Explain what the phrase " the departure times of the two buses are independent " meansb ) If you arrive at the bus stop at 9:00 how long do you expect to wait for a free bus todepart( ) If you arrive at the bus stop at 9:20 how long do you expect to wait for a free bus todepart