A student committee has 6 members-4 undergraduate and 2 graduate students. A subcommittee of 3 members is

Question:

A student committee has 6 members-4 undergraduate and 2 graduate students. A subcommittee of 3 members is to be chosen randomly so that each possible combination of 3 of the 6 students is equally likely to be selected. What is the probability that there will be no graduate students on the subcommittee?