The first thing we must do for this case is find the number of total guitarists.
 We have then:

 We now look for the relationship between the number of guitarists playing jazz alone to the total number of guitarists.
 We have then:
 
 Where,
 x: number of guitarists playing jazz alone
 From here, we clear the value of x.
 
 Then, the number of guitarists who play classical solo is:
 
 Answer:
 30 guitarists play classical solos in the contest
 
        
                    
             
        
        
        
Answer:
Its -1.9 for where point D is
 
        
                    
             
        
        
        
Answer:
The mean is 70, that's all I know. Sorry!
Step-by-step explanation:
Here's how you find the mean:
1. Add together ALL NUMBERS. (which equals 560 in this case.)
2. DIVIDE by the amount of numbers there are. (So 560 ÷ 8 = 70)
3. There's your answer! The mean of these numbers is 70. 
 I really hope this helps! Have a great day\night!
 
        
             
        
        
        
It’s 9b it’s just 4+5 with the b