Talk:2010 AIME I Problems/Problem 4
Revision as of 14:52, 5 March 2011 by Baijiangchen (talk | contribs) (Created page with 'This can also be solved with generating functions. Let <math>x^0 = 1</math> represent heads and <math>x</math> represent tails. The generating functions for these coins are <ma…')
This can also be solved with generating functions.
Let 
represent heads and 
represent tails.
The generating functions for these coins are 
,,and 
in order. (weighted)
The product is 
.
The sum of the coefficients squared is 784 and the sum of the squares of each coefficient is 246.
The probability is then 
.
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