WAEC Mathematics 2017 Objective — Question 6

Question 6 of 50 from the West African Examinations Council (WAEC) Mathematics 2017 Objective paper, with the correct answer and a full explanation.

If M={x:3≤x<8} and N={x:8<x≤12}, which of the following is True? I. 8∈M∩N II. 8∈M∪N III. M∩N=∅

A. A. III only
B. B. I and II only
C. C. II and III onlyCorrect
D. D. I, II and III

Explanation

M={3,4,5,6,7}, N={9,10,11,12}. M∩N=∅ (III true). M∪N={3,4,5,6,7,9,10,11,12}; 8 is not an element of M∪N, so II is actually false... Re-checking: since M∩N=∅ is true (III), and 8∉M∪N so II is false, and 8∉M∩N so I is false. Only III is true.

Sign up free to unlock

Score tracking
Practice history
Saved questions
Progress dashboard
Personalized sessions
Weak-topic breakdown

…and/or go further with premium services and No Ads.

Create free account

More questions from Mathematics 2017 Objective More Mathematics past papers