Answer) C. 77 
This picture shows how I got to the answer. You must set up the two expressions to equal each other and then solve for X
 
        
        
        
Answer:
![X = \left[\begin{array}{cccc}12&-24&8&16\end{array}\right]](https://tex.z-dn.net/?f=X%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D12%26-24%268%2616%5Cend%7Barray%7D%5Cright%5D)
Step-by-step explanation:
A matrix is given by
![A = \left[\begin{array}{cccc}6&-12&4&8\end{array}\right]](https://tex.z-dn.net/?f=A%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D6%26-12%264%268%5Cend%7Barray%7D%5Cright%5D) 
Now, we have to find the matrix X if  
⇒ X = 2A
Now, multiplication of a constant with a matrix means multiplication with that constant with all the terms of the matrix.
So, ![X = \left[\begin{array}{cccc}6 \times 2&-12 \times 2&4 \times 2&8 \times 2\end{array}\right]](https://tex.z-dn.net/?f=X%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D6%20%5Ctimes%202%26-12%20%5Ctimes%202%264%20%5Ctimes%202%268%20%5Ctimes%202%5Cend%7Barray%7D%5Cright%5D) 
⇒  ![X = \left[\begin{array}{cccc}12&-24&8&16\end{array}\right]](https://tex.z-dn.net/?f=X%20%3D%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcccc%7D12%26-24%268%2616%5Cend%7Barray%7D%5Cright%5D) (Answer)
 (Answer)
 
        
                    
             
        
        
        
The answer is A
if you add them all together, there are 15 employees, and only 5 have at least 10 years of experience. 5/15 simplifies to 1/3