title: Calculating percentage commission without losing desire markup
body: <p>Suppose I am selling an item with the following conditions:</p>
  
  <pre><code>cost = $100
  markup = 10%
  commission = 15%
  </code></pre>
  
  <p>If the item sells at $110, there is a $16.50 commission paid. This obviously takes me below the cost after paying commission.</p>
  
  <p>If I add the commission on top of the $110 as a buffer I get $126.50, at which point a 15% commission of $18.98 comes off that. Subtracting $18.98 from $126.50 gives me $107.52, which is below my desired 10% markup.</p>
  
  <p>What formula would I use to consistently calculate how much commission must be accounted for to ensure the profit markup is always met no matter how the variables change?</p>