Question
Fri April 11, 2014 By: Gokul

 

Expert Reply
Sat April 19, 2014
The probability of getting 15 heads for A is same as the probability of getting 30 - 15 = 15 heads for B.
 
Thus, the probability that A and B both obtain the same number of heads is equal to the sum of the heads of A and B.
 
That is, the probability of getting n heads from 2n tosses is 1 over 2 to the power of 2 n end exponent open parentheses table row cell 2 n end cell row n end table close parentheses
 
 
Thus, the probability that both obtain the same number of heads is
 
 
equals 1 over 2 to the power of 2 n end exponent open parentheses table row cell 2 n end cell row n end table close parentheses equals 1 over 2 to the power of 30 open parentheses table row 30 row 15 end table close parentheses equals 1 over 2 to the power of 30 cross times 155117520 almost equal to 0.14464
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