The equation would be 2n-7
Answer:
The percentage is 
Step-by-step explanation:
From the question we are told that
The population mean is 
The standard deviation is 
The percent of people who write this exam obtain scores between 350 and 650

Generally




From the z-table 
and 
=> 
=> 
Therefore the percentage is 

![\sf \left[\begin{array}{cc}\sf 4&\sf 6\\ \sf 5 &\sf 8 \\ \sf 3 &\sf -2\end{array}\right]-\left[\begin{array}{cc}\sf 2&\sf 3\\ \sf 1 &\sf 4 \\ \sf -5&\sf3\end{array}\right]](https://tex.z-dn.net/?f=%5Csf%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D%5Csf%204%26%5Csf%206%5C%5C%20%5Csf%205%20%26%5Csf%208%20%5C%5C%20%5Csf%203%20%26%5Csf%20-2%5Cend%7Barray%7D%5Cright%5D-%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D%5Csf%202%26%5Csf%203%5C%5C%20%5Csf%201%20%26%5Csf%204%20%5C%5C%20%5Csf%20-5%26%5Csf3%5Cend%7Barray%7D%5Cright%5D)
Just substract corresponding terms
![\\ \sf\longmapsto \left[\begin{array}{cc}\sf 2 &\sf 3\\ \sf 4&\sf4\\ \sf 8&\sf -5\end{array}\right]](https://tex.z-dn.net/?f=%5C%5C%20%5Csf%5Clongmapsto%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D%5Csf%202%20%26%5Csf%203%5C%5C%20%5Csf%204%26%5Csf4%5C%5C%20%5Csf%208%26%5Csf%20-5%5Cend%7Barray%7D%5Cright%5D)
Option B