I'm setting up an excel sheet in Microsoft Excel 2010 and I'm in need of assistance.

Column D holds Priority: Medium or High
Column B holds Ticket Date and Time
Column E holds Response Time

Column F however, holds response time in hours.
This is where I need the assistance.

I'd like to get a calculatedresult for this column. Taking away the response time from the ticket date and time.
I'd also like to produce some sort of color code for this column.
Eg:
If Medium, then Response time<8 - turn cell green
else, turn cell red
If High, then Response time<4 - turn cell green
else, turn cell red.

Really hope I can get some assistance. Still spending some time with it at the moment.