Wanted quantity - multiplying / sq m in pack

[igniter89]

Hi presta,

I have feature with id 6. This feature is number of sq meters in one pack of floor.

{if isset($features) && $features}
 {foreach from=$features item=feature}
   {if $feature.id_feature == 6}
   <div class="itemTwo">{$feature.value|escape:'htmlall':'UTF-8'}</div> 
   {/if}
 {/foreach}
{/if}

what i need is: if customer increase or decrease wanted quantity i need to show him actual info with real sq meters in his packs of floor.

For example:  
1pack with price 100$ ... i know that 1 pack is 2m². Customer change wanted quantity to 5pack and i want to show him info that 5packs for 500$ contain 10m².

 

So, is it possible something like this?:  (wanted_quantity * id_feature == 6) = value of m²  that the customer gets.

PLS see attached file 

Many thanks for fast reply and your time.