title: Sleeping by Fractions of a Time Duration
body: <p>Can someone tell me why this works:</p>
  
  <pre><code>s := time.Hour/73.0
  fmt.Println("sleeping: ", s)
  time.Sleep(s)
  </code></pre>
  
  <p>But this fails:</p>
  
  <pre><code>d := 73.0
  s := time.Hour/d
  fmt.Println("sleeping: ", s)
  time.Sleep(s)
  </code></pre>
  
  <p>This is the error:</p>
  
  <pre><code>invalid operation: time.Hour / d (mismatched types time.Duration and float64)
  </code></pre>