Problem with calculation

Problem with calculation

  2. <script language="JavaScript" type="text/javascript"> 
  3.         $(document).ready( function() {
  4.          $(".chkOptions").click(
  5.          function () {
  6.          var ntot = 0;
  7.                     var multiplier = $('#multiplier').val();
  8.                     var ans = $('.chkOptions').val();
  9.          $(".chkOptions:checked").each(function () {
  10.                         ans = multiplier * ans;
  11.          ntot += parseInt($(this).val());
  12.          });
  13.          $("#txtSavingsTot").val(ntot);
  14.          })
  15.          .change();
  16.         });
  17.         </script> 

  19. Hi I am having a problem with calculating values. Ah the first thing it should do is multiply the hidden value to the checkbox value and get the sum of the after. . 

  21. <input type="hidden" id="multiplier" value="500" />(The value value 500 is just an assumption)

  23. <input type="checkbox" class="chkOptions" value="12" />  ---- ANS
  24. <input type="checkbox" class="chkOptions" value="13" />  ---- ANS

  26.                                                                                           SUM

  28. Can u actually please help me. .  .I am stuck.  .  Thanks