Four buses carrying 140 high school students arrives in Montreal. The buses carry, respectively, 30, 42, 27, and 41 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. Compute the expectations and variances of X and Y:
