106.78/.05=2135.6
21356*.05=106.78
        
             
        
        
        
The mass of the rock in kg is 90,000 kg
        
                    
             
        
        
        
128.309728
add all numbers together and divide by 50(there are 50 numbers)
find the difference of each number and 67.92(the mean)
add all these numbers together and divide by 50
 
        
             
        
        
        
12 +4m = 24
4m = 12
m = 12/4
m = 3  so choice C. is right sure 
        
             
        
        
        
A+s=2000
5a+3s=8500
a=-s+2000
-5s+10000+3s=8500
-2s=-1500
s=750
a=1250
They sold 750 student tickets and 1,250 adult tickets