#1**+1 **

To calculate the number of happening of an event, N chooses K tool is used. N is the sum of data and K is the number that we chose from the sum of data.

The formula for N choose K formula is

:\(C(n, k)= n!/[k!(n-k)!] \)Where,

n is the total number

k is the number of selected item

Solved Examples

Question 1: How many ways to draw exactly 6 cards from a pack of 10 cards?

Solution:

From the question, it is clear that,

N = 10

N = 6

**So the formula for n choose k is,\(C(n, k)= n!/[k!(n-k)!] 610C=10!6!(10−6)!=362880017280 \)= 210**

So, there are 210 ways of drawing 6 cards in a pack of 10.

This formula and topic is very useful in solving various types of problems I recommend that you you practice this topic until you feel like you can solve and N choose K question.

Here to help

:D

LuckyDucky May 1, 2020

#4**+1 **

Anything choose 0 is 1, Anything choose 1 is the number i.e. 1 choose 1 is 1, 2 choose 1 is 2, 3 choose 1 is 3 and so on. You can't use negative numbers is combinatorics.

HELPMEEEEEEEEEEEEE May 1, 2020

#8**+2 **

Here's proof of LuckyDucky's answer of 0 choose 0

C(0,0) =

0! 1 1

__________ = _____ = _____ = 1

(0 - 0)! * 0! 0! * 0! 1 * 1

But....think about this...we have no objects and we want to choose none of them

There's only one way to do this.....forget about it !!!!

CPhill May 1, 2020

#9**+1 **

Wow, that reasoning blows my mind (JK) its very well said!

Now I have logic to back up my answer.

:D

LuckyDucky
May 1, 2020