Question

Type the formula for the number of combinations of n things taken r at a time.

C(n, r) =

Answer 1

Formula:
  Note: , where nPr is the formula for permutations of n objects taken r at a time. Example: How many different committees of 4 students can be chosen from a group of 15? Answer: There are possible combinations of 4 students from a set of 15.   There are 1365 different committees.

Answer 2

Answer: $C(n,r)=\frac{n!}{(n-r)!r!}$ where n represents the total number of objects, and r represents the number of objects being selected at a time.

Step-by-step explanation:

• Combination is a collection of the items where the order doesn't matter. It is a way to calculate the total outcomes of an event where order of the outcomes does not matter.

The formula for the number of combinations of n things taken r at a time is

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