convert element in a list to float

[forums_mp at hotmail.com]

For starters, I googled and saw a plethora of writings on how to convert an entire list from string to float.   My interest is on select elements in the list.  The output from the print statement: print scenarioList 
  
is as follows

[ '3000000', '"N"', '11400000', '"E"' ]

I need to convert the first and third element to float.  
  lat = ( float ) scenarioList [ 0 ]
  lon = ( float ) scenarioList [ 2 ]

fails (invalid syntax).  How can I achieve my objective. 

Thanks in advance