Bài 1:
uses crt;
var a:array[1..250]of integer;
t,i,n:integer;
begin
clrscr;
write('n='); readln(n);
for i:=1 to n do
begin
write('a[',i,']='); readln(a[i]);
end;
t:=0;
for i:=1 to n do
if (a[i] mod 2=0) and (i mod 2<>0) then t:=t+a[i];
writeln(t);
readln;
end.
Bài 2:
uses crt;
var a:array[1..100]of integer;
n,i,dem:integer;
begin
clrscr;
write('n='); readln(n);
for i:=1 to n do
begin
write('a[',i,']='); readln(a[i]);
end;
{-------------------------------xu-ly----------------------------}
dem:=0;
for i:=1 to n do
if (a[i] mod 3=0) or (a[i] mod 5=0) then inc(dem);
writeln(dem);
readln;
end.