Wednesday

April 23, 2014

April 23, 2014

Posted by **MathsHelpNeeded** on Thursday, August 27, 2009 at 6:34am.

This question was answered by Reiny and i was wondering how she got her andwer :

For at least 2 women and 3 men, the only cases would be

2W,4M = C(4,2) x C(7,4) = 6x35 = 210 , or

3W,3M = C(4,3) x C(7,3) = 4x35 = 140

for a total of 350 ways

I would like to know how you got the 35 in the 6 X 35 and the 4 X 35

Thank You

MathsHelpNeeded

- Maths -
**Reiny**, Thursday, August 27, 2009 at 8:03amWow, this goes back quite some time.

by definition

C(n,r) = n!/(r!(n-r)!) , so

C(7,3) = 7!/(3!4!) = 35 , and

C(7,4) = 7!/(4!3!)

Most scientific calculators contain the functions C(n,r) and P(n,r)

they are probably written as_{n}C_{r}and_{n}P_{r}

Here is a page that explains the notation and difference between combination and permutation.

http://www.mathsisfun.com/combinatorics/combinations-permutations.html

You might also google "Pascal's Triangle" to see a very interesting relationship between the values of C(n,r) and the rows of the triangle.

Look at the last row of this version of the triangle

http://mathforum.org/workshops/usi/pascal/images/fill.comb.gif

**Related Questions**

Maths - Eleven people, 7 men and 4 women, successfully completed their study at ...

gr12 math - froma group of 6 ladies and 4 men, determine in how many ways a ...

math - from a group of women and 4 men, determine in how many ways a committee ...

math - You are forming 3 teams from 25 people. Team A has 8 Team B has 3 Team C ...

Math - I'm really struggling with how to set this up: A company has 18 members ...

math - a committee of 5 people is to be selected from a group of 6 men and 9 ...

math word problem - There are 10 women and 8 men in a club. How many different ...

statistics - 6. six men and four women are standing around a table that has four...

math - In a company there are 7 executives: 4 women and 3 men. 3 are selected to...

Grammar - Diagram each sampile subject and simple predicate. 1. People arrived ...