title: Center multiple floating divs next to each other
body: <p>I'm supposed to make 3 <code>div</code>s sit next to each other. So I made a <code>div</code> and I've put three <code>div</code>s in, with this css style:</p>
  
  <pre><code>div.holder div {
    float: left;
    width: 250px;
    background-color: yellow;   
  
    /*margin-right:auto;  /**These did not help**/
    margin-left:auto;  */
  }
  </code></pre>
  
  <p>And html like this:</p>
  
  <pre><code>&lt;div class="holder"&gt;
    &lt;div&gt;&lt;/div&gt;
    &lt;div&gt;&lt;/div&gt;
    &lt;div&gt;&lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>And it's supposed to look like this:
  <img src="https://i.stack.imgur.com/2f3My.png" alt="three divs">
  And instead, it looks like this:
  <img src="https://i.stack.imgur.com/MNTQp.png" alt="three divs"></p>
  
  <p>The border <code>div</code>s should be aligned with the ending of the grey line.</p>