Вот так задача решается без массивов:
program score;
var a,b,c,d,sc:integer;
res:integer;
begin
write('Input 1st exam score:');
readln(a);
write('Input 2nd exam score:');
readln(b);
write('Input 3rd exam score:');
readln(c);
write('Input 4th exam score:');
readln(d);
write('Input pass score:');
readln(sc);
if (a+b+c+d) end.