How do I perform a calculation which depends on a dropdown and N number of selected textboxes?
<p>I hope that somebody can help me or point me in the right direction. </p>

<p>Here's what I have,</p>

<p>One select dropdown with two values
Eight checkboxes</p>

<p>The dropdown has a value of 6 or 12, the checkboxes value needs to be calculated on how many have been selected.</p>

<p>ie</p>

<p>If I select one checkbox and 6 from the dropdown I need to populate a textbox with 60<br>
If I select two checkboxs and 6 from the dropdown I need to populate a textbox with 80<br>
If I select three checkboxs and 6 from the dropdown I need to populate a textbox with 100<br>
etc etc</p>

<p>Any help greatly appreciated</p>
