Answer:
45
Step-by-step explanation:
Each handshake is between 2 people, so you need to find how many combinations of 2 can be formed from a group of 10 people.
n = 10 and k = 2:
₁₀C₂
10! / (2! (10−2)!)
10! / (2! 8!)
10 × 9 × 8! / (2! 8!)
10 × 9 / 2
45
