nRand = 10000000;
hit = 0;
for i = 1:nRand
   x = rand();
   y = rand();
   z = rand();

   if(x^2 + y^2 + z^2 < 1)
       hit = hit + 1;
   end
end

(hit/nRand)* 8 * (3/4);
%%

nRand = 10000000;
hit = 0;
for i = 1:nRand
    heads = 0;
    for b = 1:5
        if(rand() > .5)
            heads = heads + 1;
        end
    end
    if(heads == 3)
        hit = hit + 1;
    end
end

(hit/nRand);