Answer:
Step-by-step explanation:
The second one. 
 
        
             
        
        
        
Answer:
QUESTION?
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
Step-by-step explanation:
c and d
 
        
                    
             
        
        
        
Solution :
Let A = Economics, B = Mathematics
n(A) = 311, n(B) = 243, 
a). So, 
                      = 311 + 243 - 135
                      = 419
b). n(A only) = 311 - 135
                    = 176
      n(B only) = 243 - 135
                    = 108
Exactly one of these two courses 
   
   = 0.568
c). Neither economics nor mathematics
     
   
  = 0.162