Question

Write set {1, 5, 15, 25,…} in set-builder form.

(a) {x: either x=1 or x=5n, where n is a real number}

(b) {x: either x=1 or x=5n, where n is a integer}

(c) {x: either x=1 or x=5n, where n is an odd natural number}

(d) {x: x=5n, where n is a natural number}

This question was posed to me in an online quiz.

My query is from Types of Set topic in chapter Basic Structures: Sets, Functions, Sequences, Sums and Matrices of Discrete Mathematics

Answer 1

The correct option is (c) {x: either x=1 or x=5n, where n is an odd natural number}

For explanation: Set should include 1 or an odd multiple of 5.