11.
var a,b:real;
begin
write('Nhap chieu cao ban a,b: '); readln(a,b);
if a>b then write('Ban a cao hon') else
if b>a then write('Ban b cao hon') else
write('Hai ban cao bang nhau);
readln
end.
12.
var a,b:real;
begin
write('Nhap a,b: '); readln(a,b);
if b<0 the write('Phep chia khong thuc hien duoc')
else write('Ket qua la: ',a/b:0:4);
readln
end.