function [] = chap_1_prob_6(n)
% 
% Written by:
% -- 
% John L. Weatherwax                2007-07-01
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----
  
%n = 10; 

P_sum = 0; 
for ii=1:n+1, 
  P_sum = P_sum + prob_draw_first_colored_chip( ii, n );
end
P_sum 


function p = prob_draw_first_colored_chip( k, n )

switch k
  case 1, 
    p = 0; 
  case 2,
    p = 1/n; 
  otherwise,
    p = 1; 
    for ii=1:k-2,
      p = p*(1-ii/n);
    end  
    p = p*(k-1)/n; 
end