title: How to subtract 30 minutes from a date
body: <p>I am getting date value date: 2013-06-07 18:30:00 +0000. I am trying to subtract 30 minutes from this, but it not giving proper time.</p>
  
  <p>I've tried this</p>
  
  <pre><code> NSTimeInterval secondsPerHour = 60*30;
   NSDate *newDate = [date dateByAddingTimeInterval:-secondsPerHour];
  </code></pre>