title: Can Excel increase Cell 1 until Cell 2 matches Cell 3
body: <p>I am trying to figure out a way to get Excel to increase a cell, A1, that controls another cell, B1, until B1 equals a constant cell, C1.</p>
  
  <p>For instance, the industry standard to do a task is 4000 hours and is a constant; cell C1 = 4000.
  Cell A1 is the number of work weeks my team must work to finish this task. Cell A1 drives a lot of calculations but arrives at cell B1, which is the work Hours necessary to complete the task.  I must change the work weeks (A1) to change the work hours (B1) to match the standard.  Changing A1 changes B1 (on a wicked curve, which negates using a straight up formula).  I need B1 to equal C1 by letting Excel change A1.  A1 will then automatically tell me how many weeks the team should work.  I cannot find a formula and I don't know how to increment A1.</p>
  
  <p>The examples below show me hand-jamming A1 which moves B1 closer to matching C1.  C1 then gives me the proper number of weeks based on my </p>
  
  <pre><code>A1=10.00 B1=1900 C1=4000
  A1=15.00 B1=2850 C1=4000
  A1=20.00 B1=3800 C1=4000
  A1=21.06 B1=4000 C1=4000
  </code></pre>
  
  <p>Ideas?</p>