conditional formatting excell 2010,, as per attached sheet how i can apply conditional formatting in coloum b : 
10	9
20	10
30	25
40	18
50	27
60	50
70	55
80	40
90	30
100	150
	
I want conditional formatting in b Colosseum less the a column[enter image description here][1]	


  [1]: http://i.stack.imgur.com/rY4Ei.jpg