ANSWER
This is a basic counting principles, If there are k1 ways to do one task, and k2 ways to do another, then there are k1*k2 ways of doing both.
In this problem
k1 = 1O ways to choose first person to be chosen from the group of 10.
k2 = 9 ways for the second person to be chosen from the remaining people(10–1).
k3 = 8 ways for the second person to be chosen from the remaining people(9–1).
then all you need to do is multiply these k1 * k2 * k3.
Ans : 10 * 9 * 8 = 720
I HOPE ITS HELPFUL THIS ANSWER
