[jQuery] Calculate form sections into form total

[Nic Hubbard]

I am wondering what the best practice is for calulating form sections
into a form total.  E.g., the top of the form has some radio buttons
with price values, when a value is selected the total field at the
bottom of the form is updated.  There is also a set of checkboxes with
values, with a click event, clicking any of these will update the
value of the total input field.

The problem I run into is calculating vars when they are inside
different functions.  How does one go about doing this?

Here is what I have:

//Find if user is attending
        $('#attendingOptions input').change(function() {
        if ($('#q38480_q1_0:checked').length === 1) {
         var attendVal = 175;
         $('#q38487_q1').val('175');
        } else {
         var attendVal = 0;
         $('#q38487_q1').val('0');
        }
        });

        //Calculate awards lunch value
        var lunchVal = parseInt($('#q38481_q3').val()) * 50;

    $('#sponsorOptions :checkbox').click(
    function() {
      var valueStart = 0;
      $('#sponsorOptions input:checkbox:checked').each(function() {
        valueStart += parseInt($(this).val());
      });
      $('#q38487_q1').val(valueStart + attendVal);
    })

Right now the calculation does not work because attendVal is inside
another function.