function demere2(numreps,numrolls)
% How many rolls until we get a double-six? Here numreps is the number of
% trials and numrolls is an optional argument, the number of rolls per
% trial (which is taken to be 25 if no value is given).
%
% If you want a plot, uncomment the line with the plot command.
reps=numreps;
rec=NaN(1,reps); % where we'll keep the record
 
p=1/36; % prob of success on a given roll

for k=1:reps
    
n=1;
while rand>p
    n=n+1; % one more try
end

rec(k)=n;
end

if nargin < 2 % check to see if the optional numrolls is given and if not use 25
    numrolls = 25;
end

% plot(sort(rec))
disp(['The proportion of trials with a double 6 in the first ', num2str(numrolls), ' is ', num2str(length(find(rec<=numrolls))/reps)])