title: How to increase a double by 3%
body: <p>I would like the price to change whenever the checkbox is checked and to revert back if it is unchecked.</p>
  
  <p>This is what I have so far:</p>
  
  <pre><code>if (chkbBreakfast.Checked) // checks if breakfast is checked 
  {
      sBreakFast = "Yes";
      CGlobals.sBreakFast = "YES";
  
      double dPercent;
      dPercent = 0.03;
  
      double dtotal = Convert.ToDouble(CGlobals.sPrice) * dPercent / 100;
  
      CGlobals.sPrice = Convert.ToString(dtotal);
  
      lblTotalCost.Text = CGlobals.sPrice;
  }
  else
      sBreakFast = "No";
  </code></pre>