Câu 23 : 

if b mod 2 = 0 then writeln('b la so chan') else writeln('b la so le');

Câu 24 :

uses crt;

var tg_Rua, tg_oc : integer;

begin

clrscr;

write('thoi gian rua ve dich : ');readln(tg_Rua);

write('thoi gian tho ve dich : ');readln(tg_oc);

if tg_Rua > tg_oc then writeln('oc thang');

if tg_Rua < tg_oc then writeln('rua thang');

if tg_Rua = tg_oc then writeln('khong ai thua');

readln

end.

C1:

if b mod 2=0 then writeln('b la so chan') else writeln('b la so le');

C2:

uses crt;

var tgRua,tgoc:integer;

begin

write('nhap thoi gian rua chay:');readln(tgRua);

write('nhap thoi gian oc sen chay:');readln(tgoc);

if tgRua> tgoc then writeln('Oc sen chay nhanh hon rua') else

if tgRua< tgoc then writeln('Oc sen chay cham hon rua') else

writeln('Rua va oc sen chay nhanh bang nhau');

readln;

end.