<h3>
Answer: 680 different combinations</h3>
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Explanation:
If order mattered, then we'd have 17*16*15 = 4080 different permutations. Notice how I started with 17 and counted down 1 at a a time until I had 3 slots to fill. We count down by 1 because each time we pick someone, we can't pick them again. 
So we have 4080 different ways to pick 3 people if order mattered. But again order doesn't matter. All that counts is the group itself rather than the individual or how they rank. There are 3*2*1 = 6 ways to order any group of three people, which means there are 4080/6 = 680 different combinations possible. 
An alternative is to use the nCr formula with n = 17 and r = 3. That formula is

where the exclamation marks indicate factorials
 
        
        
        
2x² + 5x -6x - 15 = 0
2x² - x - 15 = 0
2x² -x = 15
x = 3
3 x 3 = 9 x 2 = 18 - 3 = 15
i really don't know how i got 3 in the first place but that is your answer
hope this helps
        
             
        
        
        
Answer:
1. b
2. I'm not sure about this one
Step-by-step explanation: