Find the number of subsets of the set {1, 2, 3, 4, 5, 6, 7, 8, 9, 10} having 3 elements.

Is the sentence true or false?

We denote the number of unique r-selections or combinations out of a group of n objects by nCr.

 Find number of ways to choose 2 Prizes from a Set of 6 Prizes.

A group of 3 lawn tennis players S, T, U. A team consisting of 2 players is to be formed. In how many ways can we do so?

Find number of ways to choose 3 Students from a Class of 25.

Suppose we have a set of 6 letters { A,B,C,D,E,F}. In how many ways can we select a group of 3 letters from this set?

Find number of ways to choose  4 Menu Items from a Menu of 18 Items.

Complete:

The number of ways to choose a sample of r elements from a set of n distinct objects where order does not matter and replacements are not allowed is called _________.

 Complete:

Combinations are also called____________.

Is the formula true or false?

$nCr=\frac{n!}{r!(n-r)!}$