Discuss the below:
Q: A professor grades homework by randomly choosing 5 out of 12 homework problems to grade.
a) How many different groups of 5 are there from the 12 problems?
b) Jerry did only 5 problems of one assignment. What is the probability that the problems he did comprised the group that was selected to be graded?
c) Silvia did 7 problems. How many different groups of 5 did she complete? What is the probability that one of the groups of 5 she completed comprised the group selected to be graded.