State whether the following sets are finite or infinite:

(a) Set of all whole numbers

(b) Set of odd numbers between 3 and 15

(c) Set of months in a year

(a) The set of all whole numbers is 0, 1, 2, 3, … which goes on without end, so it is an infinite set.

(b) The set of odd numbers between 3 and 15 is {5, 7, 9, 11, 13}, which has a countable number of elements, so it is a finite set.

(c) The set of months in a year has 12 elements, so it is a finite set.

Hence, (a) Infinite, (b) Finite, (c) Finite.