Question : A total of 4 buses carrying 148 student from the same school arrive at a football stadium. The buses carry 40, 33, 25 and 50 students. One of the students is randomly selected. Let X denote the number of students that were on the bus carrying this randomly selected student. One of the 4 bus drivers is also randomly selected. Let Y denote the number of students on his bus.

i) Which of E[X] or E[Y] do you think is larger? Why ?

ii) Compute E[X] and E[Y]

---------------------------------------My Work-----------------------

Bus A --------Pr(Student from A) = $\displaystyle \frac{40}{148}$

Bus B --------Pr(Student from B) = $\displaystyle \frac{33}{148}$

Bus C --------Pr(Student from A) = $\displaystyle \frac{25}{148}$

Bus D --------Pr(Student from A) = $\displaystyle \frac{50}{148}$

X would be the number of student from the bus chosen

but i dont know what to do ???