Answer:
a) 7.5/3=2.5  
b)  about 3 pieces can be cut.
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
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Step-by-step explanation:.........................................................................................................................
 
        
             
        
        
        
Take the cross product, then normalize the result.

This has norm

and so a unit vector orthogonal to both given vectors is

An equally correct answer would be the negative of this vector, since 

.