A seminar on public policy consists of 5 students majoring in economics and 3 students majoring in political science. A group of 3 students is selected at random by the professor to prepare a report on farm subsidies.

a) What is the probability that the group contains no political science majors

b) What is the probability that it contains at least one economics major given that it contains at least one political science major? (Do not to bother to do the calculations)