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Basic Math/Permutations

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Expert: Josh - 3/27/2009


Question
I am making a tennis schedule. There are 12 players; 8 of the 12 players play each week on 2 tennis courts. How many combinations are there? I number the players 1 through 12.

Answer
Hi Kara,

The number of combination is given by C(12,8)=12!/[(12-8)!8!], where n! is defined as n*(n-1)*(n-2)*...*2*1 and 0!=1 by definition.

If you are interested, look up "permutation and combination" on a search engine. You will find plenty of explanation and examples on this formula.

The answer is (12*11*10*9)/(4*3*2*1) = 495

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Josh

Expertise

When I work through problems, I like to emphasize concepts which I believe are worth noting. I will try to answer questions in the following areas, but not at the advanced level. Algebra. Sequences & Series. Trigonometry. Functions & Graphs. Coordinate Geometry. Quadratic Polynomials. Exponential & Logarithms. Basic Calculus. Probability, Permutation and Combination. Mathematical Induction. Complex numbers. Physics problems.

Experience

I have worked as a teaching assistant in college. My hope is that more people will share knowledge without boundary, give help without seeking recognition or monetary rewards.

Education/Credentials
Bachelor degree in Engineering Science

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