The inclusion/exclusion principle states that

That is, the union has as many members as the sum of the number of members of the individual sets, minus the number of elements contained in both sets (to avoid double-counting).
Therefore, 

 will have the most elements when the sets 

 and 

 are disjoint, i.e. 

, which would mean the most we can can in this case would be

(Note that 

 denotes the cardinality of the set 

.)
 
        
        
        
Answer:
Let them defrost first, then heat them up for a couple of minutes in the toaster. 
Step-by-step explanation:
 
        
             
        
        
        
Answer:
(a) 0.2707
(b) 0.8576
Step-by-step explanation:
 
        
             
        
        
        
Your answer is true! I hope that helps ;)