So we are given that the mean is 42% and the sd (standard deviation) is 8%
Assuming our data is normal we can use the 68-95-99 rule
So one thing you should realize is that 42% + 8% is 50% which is passing. That is one standard deviation higher. So we use:
 
100 - 68 - 13.5 - 2.35 - 0.15  = 16. That means 16% of students passed the test. Which is terrible. They probably need to hit the books more.
Anyways if you have any question feel free to message me!
Hopes this helps!
        
             
        
        
        
Answer:

Step-by-step explanation:
Use the square of a binomial theorem
 =
= 
Now expand the given equation:

Hope this helps :)
Have a great day!
 
        
             
        
        
        
Answer:
-3f - 10
Step-by-step explanation:
-1 times 10 = -10
-1f times 3f = -3f
Sorry if this isn't right.
 
        
                    
             
        
        
        
14/1 or 14 that could be your answer good luck:)