title: convert float to hours using momentjs
body: <p>For example, how to convert this float number 6.5 to "06:30" using momentjs?</p>
  
  <p>I've tried this:</p>
  
  <pre><code>moment("6.5", "hh:mm").format("HH:mm"))
  </code></pre>
  
  <p>but it outputs:</p>
  
  <pre><code>06:05
  </code></pre>