3. Two mark exercise problems I

If $P =\{1, 2, 5, 7, 9\}$, $Q = \{2, 3, 5, 9, 11\}$, $R = \{3, 4, 5, 7, 9\}$ and $S = \{2, 3, 4, 5, 8\}$, then find (i) $(P \cup Q) \cup R$ (ii) $(P \cap Q) \cap S$ (iii) $(Q \cap S) \cap R$

 

Answer:

 

(i) $(P \cup Q) \cup R =$$\left\{i,i,i,i,i,i,i,i\right\}$

 

(ii) $(P \cap Q) \cap S =$ $\left\{i,i\right\}$

 

(iii) $(Q \cap S) \cap R =$$\left\{i,i\right\}$

 

(Note: Enter the numbers in ascending order.)