This will do it (though there might well be a neater way!):
A = [70 90 80; 90 90 90; 80 60 70];
B = [0.5 0.8 1.0; 0.2 0.5 1.0; 0.3 0.2 0.5];
A = A(:); B = B(:); C = sortrows([A B]);
k = 0;
for i = 60:10:90
ix = C(:,1)==i;
k = k+1;
bin(k) = sum(C(ix,2));
ix = [];
end
