title: reduce time when a different cell is blank
body: <p>I am trying to build a program in Excel where if data is entered into a cell, the time will reduce in another cell.</p>
  <p>I have 2 columns. One currently calculates slots based on blank cells. This is working fine using COUNTBLANK.</p>
  <p>=COUNTBLANK('E1&amp;3'!C3:C7)+COUNTBLANK('E1&amp;3'!C16:C44)+COUNTBLANK('E1&amp;3'!C50:C60)+COUNTBLANK('E1&amp;3'!C68:C70)+COUNTBLANK('E1&amp;3'!C76:C96)+COUNTBLANK('E1&amp;3'!C101:C102)</p>
  <p>I have another which calculates hours available and again this is working fine using =SUM.
  =SUM('E1&amp;3'!B3:C7)</p>
  <p>What I want to do is combine these where if a cell becomes blank the time will increase, and if not blank it will decrease and I am not sure how to do that. I know that you can not have 2 different formulas at once within a cell, so I am trying to figure out the combined formula.</p>
  <p>Any advice would be great.</p>