How to divide two different array in for loop matlab

I am sorry for such a stupid question. I am not very good in programming and I am bad in MATLAB as well.

I need help to my problem. I am generating a code where it has 30 variables (denoted by u). I used for loop for this. My code will produce value and the position with each variables.

My problem is how to locate and divide variable 1 to variable 16, variable 2 to variable 17, variable 3 to variable 18....until it reach variable 15 divided to variable 30. I have MATLAB files attached to this question. Any help would be appreciated.

This is the main file

start=zeros(2,15);
a=[-12 10 -5 3 21 19 3 7 17 21];

for u = 1:30;   
    acx = rand();
    newacx = round(acx*100);

    if (newacx < 10 || newacx == 10)
       [valueone,positionone] = randomFunction(a); 
    elseif (newacx > 10)
       [valueone,positionone] = max(start(1,:));
    end

    result(u) = valueone 
    % I want to divide result(1)/result(16),result(2)/result(17)...until result (15)/result(30)

    resultX(u)= positionone 
    % I need to identify the position, which I can call when I need to analyze the data

end

This is the function file related to m-file

function [value,position]= randomFunction(a)

y=randperm(length(a));
position=y(1);
value=a(position);

end