yogi_Work Around For Conditionally Formatting Dates In A Column Based on A Formula

Yogi Anand, D.Eng, P.E.       Google Spreadsheet    Post  #512    Apr 19, 2012     www.energyefficientbuild.com.

user GavinP said:
Google Spreadsheet - Conditional Formatting Question
I have a spreadsheet containing various values.  One column, column I (i) contains a list of dates. 

I need each date to appear RED if

1) The date is Today (I can do this)

2) The date is any date prior to Today (I can do this)

3) The date is 20 days in the future from Today (I can't do this)

1) and 2) are easy to do. I can not for the life of me work out how to do 3) on Google Spreadsheets.  There is no simple option to click 'If the date is 20 days in the future...'.  

Could someone help me please?  

----------------------------------------------------------------------------------------------

following is a solution to the problem ... since one can not use directly a formula for conditional formatting, I have colored cells of adjacent column J in place of cells in column I