clc;
clear all;

A=[0   9  -4  20
   8   2   4  10
   2  -2   4   7];

s1=0;
s2=0;

for i=1:size(A,1)
    s1=s1+A(i,4);
end

for j=1:size(A,2)
    s2=s2+A(2,j);
end

M1=s1/size(A,1);
M2=s2/size(A,2);

fprintf('Mean value of 4th column is: %.2f\n',M1);
fprintf('Mean value of 2nd row is:     %.2f\n',M2);