1.

Determine the set of all integers a such that a ≡ 3 (mod 7) such that −21 ≤ x ≤ 21.(a) {−21, −18, −11, −4, 3, 10, 16}(b) {−21, −18, −11, −4, 3, 10, 17, 24}(c) {−24, -19, -15, 5, 0, 6, 10}(d) {−23, −17, −11, 0, 2, 8, 16}I have been asked this question at a job interview.I would like to ask this question from Relations in chapter Relations of Discrete Mathematics

Answer»

The correct answer is (b) {−21, −18, −11, −4, 3, 10, 17, 24}

For explanation I would say: For an INTEGER a we have X ≡ 3 (mod 7) if and only if a = 7m + 3. Thus, by calculating multiples of 7, add 3 and RESTRICT the value of a, so that −21 ≤ x ≤ 21. The SET for a = {−21, −18, −11, −4, 3, 10, 17, 24}.



Discussion

No Comment Found

Related InterviewSolutions