I have two queries on formula...

1 - I am trying to calculate two fields based on a checkbox and get a syntax error message. The formula is: If the check box is true then add field 1 and field 2.

2 - I need to calculate a ratio based on a pick list response. For this I am trying to use IF. Formula being: If pick list is 40 then add field 1 and field 2 and divide the total by 40. If the pick list is 30 the. divide the total by 30

Any assistance much appreciated!