How many randomly assembled people do u need to have a better than 50% probability that at least 1 of them was born in a leap year?  Choose the correct choice from the following choices:  A) 3  B) 9  C) 27  D) 54  E) 81
Prob[at least one of them was born in a leap year] &gt; 50%   Since P(A) = 1 - P(A')   1 - Prob[none of them was born in a leap year] &gt; 1/2   Prob[none] - 1 &lt; -1/2   Prob[none] &lt; 1/2   Assume that there are n people.   Prob[none] = (3/4)^n   (3/4)^n &lt; 1/2   3^n &lt; (4^n)/2   3^n &lt; (2^2n)/2   3^n &lt; 2^(2n-1)   If n = 3, 3^3 &lt; 2^5 is true   3 is the answer
<result>A</result>
How many randomly assembled people do u need to have a better than 50% probability that at least 1 of them was born in a leap year?