There are 40 students in a youth club. A certain number like playing tennis, another number of students like playing computer games and 8 students like neither.
(i) Calculate the value of x in the Venn diagram shown, and complete the Venn diagram.
Tennis 20 – x x 15 – x
(ii) How many students like playing tennis and computer games? (iii) If a student is selected at random, calculate the probability they do not like playing tennis.
Solution (i)
8
핌
Computer games
(ii) (iii)
Practice questions 6.1
1. Explain what a mathematical set is and give an example. 2. The following table contains a list of statements which may or may not be a mathematical set. Copy and complete the table.
Mathematical set? (i) (ii)
A = {vowels in the alphabet} B = {good pizza toppings}
(iii) C = {irrational numbers} (iv)
(v) (vi) (vii)
D = {All-Ireland Gaelic football winners} E = {easy subjects in my school} G = {old people in the world} H = {best phone apps}
(viii) I = {natural numbers}
3. Copy and complete the table. Word
(i) Null set (ii) Union
(iii) Not an element (iv) Subset (v)
Intersection
(vi) Complement (vii) Cardinal number
108 Linking Thinking 2 Meaning in words The elements of two sets combined ∩ Notation True/False Reason for your answer