JQuery hide Class if other class is visible

I know this question already have asked before and i also tried the answer and it almost worked for me but there is one issue which i can't able to sort i tried plenty of ways but all in wain. This is the div i want to hide

    <div class="price-box" itemprop="offers" itemscope="" itemtype="http://schema.org/Offer">

       <p class="price"><span class="special-price" style="display: none;">
        <span class="amount">$43.50</span>
        </span>
       </p>
    </div>

when this div is not empty

<div class="single_variation"><span class="price"><span class="amount">$43.50</span></span></div>

This is what i implement

  jQuery(document).ready(function() {

    if( jQuery('.single_variation').is(':empty') ){
      alert('hi');
        jQuery('.price-box').show();
      }

});

and also

if($('.price').length){ $('.price-box').hide(); }

via Chebli Mohamed