A group of ten seniors, seven juniors, five sophomores, and four freshmen must select a committee of four. How many committees are possible if the committee must contain the following? (a) one person...

Extracted text: A group of ten seniors, seven juniors, five sophomores, and four freshmen must select a committee of four. How many committees are possible if the committee must contain the following? (a) one person from each class (b) any mixture of the classes (c) exactly two seniors