function demere1(numreps)
% demere1(n) finds the number of rolls until we get a 6 and records the 
% the number of rolls. It repeats n times and displays the proportion of
% times the number was at most 4.
%
% It also shows a plot of how many times a given number of rolls was
% required to get a 6. 
reps=numreps;
rec=NaN(1,reps); % where we'll keep the record
 
for k=1:reps
    
n=0;
gotit=false;
while not(gotit)
    n=n+1; % one more roll
    roll=ceil(6*rand);
    if roll==6
        gotit=true;
    end
end

rec(k)=n;

end

plot(sort(rec))
hold on
plot([1 reps],[4 4],'--m')
hold off
disp(['The proportion of trials with a 6 in the first 4 rolls is ', num2str(length(find(rec<=4))/reps)])