Question: A student must answer exactly eight questions out of ten on a final examination.
(a) In how many ways can she choose the questions to answer?
(b) Repeat (a) if she must answer the first three questions.
(c) Repeat (a) if she must answer at least three of the last five questions and at most four of the first five.
(d) Repeat (a) if she must answer at least three of the last five questions.