Thib33600 wrote:
NoHalfMeasures wrote:
By fundamental counting principle,
Total No of out comes: 2^4 = 16
Total Desired outcomes: No of ways to arrange BBGG by MISSISSIPPI rule= 4!/(2!*2!) = 6
Probability is 6/16 = 3/8
Could please explain that MISSISSIPPI rule?
THEORY Permutations of \(n\) things, of which \(P_1\) are alike of one kind, \(P_2\) are alike of a second kind, \(P_3\) are alike of a third kind, ... \(P_r\) are alike of \(r_{th}\) kind such that: \(P_1+P_2+P_3+...+P_r=n\), is:
\(\frac{n!}{P_1!*P_2!*P_3!*...*P_r!}\)
For example, the number of permutations of the letters of the word "gmatclub" is \(8!\), as there are 8 DISTINCT letters in this word.
The number of permutations of the letters of the word "google" is \(\frac{6!}{2!2!}\), as there are 6 letters, with "g" and "o" each appearing twice.
The number of permutations of 9 balls, out of which 4 are red, 3 green, and 2 blue, would be 9!/4!3!2!.
The number of permutations of the letters of the word "ILLUSION" is \(\frac{8!}{2!2!}\), as there are 8 letters, with "L" and "I" each appearing twice.
21. Combinatorics/Counting Methods
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