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January 27th, 2011, 04:03 PM  #1 
Newbie Joined: Feb 2009 Posts: 21 Thanks: 0  Probability question
Question : How many times should a coin be tossed so that the probability of at least one head is >= 99% Attempt, straight from the definition : P(N = n) = (1p)^(n1) * p, where p is the probability of success 0.99 = (11/2)^n * 1/2 0.99 = (1/2)^n n = 0.0145 What am I doing wrong? 
January 27th, 2011, 04:31 PM  #2  
Global Moderator Joined: Nov 2006 From: UTC 5 Posts: 16,046 Thanks: 938 Math Focus: Number theory, computational mathematics, combinatorics, FOM, symbolic logic, TCS, algorithms  Re: Probability question Quote:
You should set the odds of getting all tails to 1% and solve.  

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