the gender of the kids does not matter so it can be discarded. 
you add up how many boys and girls in the class to make a total of 50 kids
your 100% is 50
meaning 40% of 50 is 20
so if 20 kids took the bus to school then 30 did not take the bus.
 
        
             
        
        
        
Answer:
there is one real solution
Step-by-step explanation:
use the quadratic formula. what is in the square root is called the discriminant. 
since it came out to 0 there is one real solution
 
        
             
        
        
        
One can solve this by first using order of operations, and then combining like terms.
First is parenthesis
9x + 2x(9) - 2(9x)
Now we do the multiplication
9x + 18x - 18x
Now we combine like terms
9x
 
        
             
        
        
        
Answer:
Step-by-step explanation:
add a picture of the question please