To find 15% of 23000, 
 23000 x (15/100) = 23000 x 0.15 = 3450
So her salary for the month would be $3450.
        
                    
             
        
        
        
Answer: 1/3
Step-by-step explanation:
 
        
             
        
        
        
The result of the fraction is 3.5
we can calculate this like this:

I think that the question is asking between which two natural numbers the result lies, and the result is 3 and 4: it's bigger than 3 and smaller than 4 
 
        
        
        
To answer this item, we take the differential of the equation and equate to zero.
 
                  C(x) = 0.8x² - 256x + 25939
Differentiation,
                dC(x) = 1.6x - 256 
                 dC(x) = 1.6x - 256 = 0
The value of x from the derived equation above is 160. 
Thus, the number of machine to be made in order to minimize the cost should be 160. 
        
                    
             
        
        
        
You know you have two hours which will be the whole number. Then you take 36min and put it over 60min (total number of min in an hour) and you simplify by 6 to get 6/10 which can be simplified again to 3/5 so your final mixed number is 
2 and 3/5 hours