## Intersection of Sets

 4.1 Intersection of Sets

Determine and describe the intersection of sets using various representation.

• Intersection of sets exist when there are more than one set.
• The intersection of set $$P$$ and $$Q$$ is written using the symbol $$\cap$$
• Example: Set $$P \cap Q$$ contains the common elements of both sets   $$P$$ and $$Q$$ .

 Example The intersection of a set $$R$$, a set $$S$$ and a set $$T$$, represented as $$R ∩ S ∩ T$$, is a set whose elements consist of all common elements of a set $$R$$, a set $$S$$ and a set $$T$$. The intersection of set can be represented by using Venn Diagrams

 Example 2 A total of $$140$$ Form $$4$$ pupils are given the opportunity to attend the intensive classes for Mandarin an Bahasa Melayu subjects. $$65$$ pupils choose Bahasa Melayu, $$70$$ pupils choose Mandarin while $$50$$ pupils choose both.  Calculate the total number of pupild who attend the intensive classes. Solution: Steps: Fill in $$n(B\cap M)= 50$$ Fill in the number of pupils who attend Bahasa Melayu class only $$(65-50=15)$$ Fill in the number of pupils who attend Mandarin class only $$(70-50=20)$$ Thus, people who attend intensive class $$(15+50+20= 85)$$