title: PHP: Time difference (min:sec:tenths)
body: <p>How can I calculate time difference when operating with <code>minutes:seconds.tenth</code> ?<br>
  For example how can I achieve this example: <code>40:24.5 - 67:52.4 = -27:27.9</code></p>
  
  <p>I was going to use this but then discovered lack of tenths:</p>
  
  <pre><code>$time1 = new date('40:24.5');
  $time2 = new date('67:52.4');
  $interval = $time1-&gt;diff($time2);
  echo $interval-&gt;format('%R%%i:%s:??');
  </code></pre>