title: Split a percentage over 3 fields?
body: <p>I've got 3 cells in my spreadsheet that have the layout as below.  These values are dynamic, however what I need to do is split a percentage over the 3 fields, and then increase the number.</p>
  
  <pre><code>Total Staff Costs           £1,000.00
  Total Hardware Costs        £0.00
  Total Expenses              £400.00
  </code></pre>
  
  <p>For instance, the above comes to a total of £1400, however I need to charge 10% of my own time on top of this so £140.</p>
  
  <p>What I can't just do though, is take this 10% and split it over the 3 fields, ie. I can't just add £46.70 to each field, because no hardware has been bought, so to say its £46.70 would raise some questions.  I need to split it proportionally between each one. </p>
  
  <p>How can I go about adding X% to the fields proportionally?</p>