I think it's 64. Not positive, but pretty sure it is. 
        
                    
             
        
        
        
10/18 because 18-8=10 and the total amount is 18 so the fraction is 10/18
        
                    
             
        
        
        
Answer:
 degrees Fahrenheit
 degrees Fahrenheit
Step-by-step explanation:
Let  be temperature.
 be temperature.
 at 3:00PM:
 at 3:00PM:  degrees.
 degrees.
Every hour, the temperature falls by  degrees per hour for the next four hours. Let's multiply 2.5 by 4 to find out the total temperature drop in four hours.
 degrees per hour for the next four hours. Let's multiply 2.5 by 4 to find out the total temperature drop in four hours.

In four hours, the temperature dropped 10 degrees. Since it is getting colder, let's subtract this from the original 5.5 degrees to get the temperature at 7:00PM.

The temperature at 7:00PM was -4.8 degrees Fahrenheit.