## Permutations Combinations IB math HL

Discussions for the Core part of the syllabus. Algebra, Functions and equations, Circular functions and trigonometry, Vectors, Statistics and probability, Calculus. IB Maths HL Revision Notes

### Permutations Combinations IB math HL

Permutations Combinations - IB Mathematics HL - IB maths Higher Level

How can we find the number of possible choices for choosing a sub-committee of five persons consisting of the chairperson, secretary and three ordinary members from a committee of 40 people?

Thanks
Jack

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Joined: Mon Jan 28, 2013 8:08 pm

### Re: Permutations Combinations IB math HL

Permutations, Combinations - IB Maths HL

The chairperson can be chosen by $^{40}\mathrm{C}_1$ ways

The secretary can be chosen by $^{39}\mathrm{C}_1$ ways

And the three ordinary members can be chosen by $^{38}\mathrm{C}_3$ ways

So, the members of this sub-committee can be chosen by

$^{40}\mathrm{C}_1 \cdot ^{39}\mathrm{C}_1 \cdot ^{38}\mathrm{C}_3 =$

$=40 \cdot 39 \cdot 8436 =13,160,160$ ways.
elizabeth

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Joined: Mon Jan 28, 2013 8:09 pm

### Re: Permutations Combinations IB math HL

Thank you!!
Jack

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Joined: Mon Jan 28, 2013 8:08 pm