Untitled

<html>
<head>
  <meta http-equiv="content-type" content="text/html; charset=utf-8" />
  <meta name="language" content="en" />
  <meta http-equiv="content-language" content="en" />
  <title>Test</title>
  <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
</head>
<body>
<script>
function calcul() {
var total = parseInt($('#studenttut option:selected').val()) +
    parseInt($('#campusrb>option:selected').val()) *
    parseInt($('#yearsatten>option:selected').val());
    $("#total").text(total);
}
</script>
<select id="studenttut">
  <option value="5">5</option>
  <option value="10">10</option>
</select>
<select id="campusrb">
  <option value="0">0</option>
  <option value="1">1</option>
</select>
<select id="yearsatten">
  <option value="1">1</option>
  <option value="2">2</option>
</select>
<input type="button" onClick="calcul()" value="calcul"/>
<div id="total">total</div>
</body>
</html>