10C6 = 10!/(6!*(10-6)!) = 10*9*8*7/(4*3*2*1) = 210
There are 210 ways to choose 6 from a group of 10.
        
                    
             
        
        
        
Answer:
6
Step-by-step explanation:
Firstly, this is the pythagoreans theorem a^2+b^2=c^2
Now that we know that, we will solve for x.
(x+2)^2+x^2=100 ( The 100 is just 10 squared )
Finally, you solve for x and get 6.
 
        
                    
             
        
        
        
Let same number of hours = x, 
since the salary earned is also the same, then
Salary of supervisor A = $25x
Salary of supervisor B = $20(30)+$30(x-30)
Equating
25x=600+30(x-30)
30x-25x=900-600
5x=300
x=60 hours
Check: 
Salary of supervisor A = 25*60=1500
Salary of supervisor B =  20*30+30*(60-30)=600+900=1500, ok.
        
             
        
        
        
Answer:

Step-by-step explanation:
Please see the attached pictures for the full solution.