25%
since there are 4 books, and only one is a mathematics book, there is a 1/4 chance.  in other words, 25%
        
                    
             
        
        
        
If a plane flies an average of 325 miles per hour, to find out 7 hours you will need to times 325 by 7. 
325 x 7 = 2275. 
therefore the flight for 7 hours was 2275 miles.
        
             
        
        
        
Answer: 
Step-by-step explanation:
We write a function f(x) which gives the values of the function that are dependent on the independent variable "x".
Given: The number of miles on the odometer can be represented by the equation y = x + 40, 000, where y is the number of miles on the odometer, and x is the number of miles you have driven it. 
Here y is dependent on x, so we replace y by f(x), then we get
 which is the required answer.
   which is the required answer.
 
        
             
        
        
        
Let the number be x.  Then 1.25x = 325, or x = 260.  
20% less than 260 is 0.80(260) = 208