1/

program B1;
uses crt;
var kw:array[1..100]of integer;
    i,tien1,tien2:integer;
Begin
    clrscr;
    for i:=1 to 12 do
    begin
        write('So dien thang ',i,': ');readln(kw[i]);
    end;
    for i:=1 to 5 do tien1:=tien1+kw[i];
    for i:=6 to 12 do tien2:=tien2+kw[i];
    write('Tien dien dung trong 1 nam: ',tien1*15800+tien2*20200,' d');
    readln
End.

2/

- Cách 1:

program B2;
uses crt;
var x,y,z:integer;
Begin
    clrscr;
    write('x = '); readln(x);
    write('y = '); readln(y);
    writeln('Hai so vua nhap: ',x,', ',y);
    z:=x;
    x:=y;
    y:=z;
    writeln('Hai so sau khi hoan doi:');
    writeln('x = ',x);
    writeln('y = ',y);
    readln
End.

- Cách 2:

program B2;
uses crt;
var x,y:integer;
Begin
    clrscr;
    write('x = '); readln(x);
    write('y = '); readln(y);
    writeln('Hai so vua nhap: ',x,', ',y);
    x:=x+y;
    y:=x-y;
    x:=x-y;
    writeln('Hai so sau khi hoan doi:');
    writeln('x = ',x);
    writeln('y = ',y);
    readln
End.

rogram ct;
uses crt;
var sodien: array[1..12] of integer;
    i,sum,sum2:integer;
begin
    clrscr;
    for i:=1 to 12 do
        begin
        writeln('Nhap so luong dien thang ',i,': ');readln(sodien[i]);
        end;
    sum:=0;
    for i:=1 to 5 do
        sum:=sum+sodien[i];
    sum2:=0;
    for i:=6 to 12 do
        sum2:=sum2+sodien[i];
    writeln('Tong tien dien la: ',sum*15800+sum2*20200);
    readln;
end.

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