Question: how to calculate business days in salesforce?
Answer:  CASE( MOD( Datevalue( Date_Finished__c ) - datevalue(Date_Received__c) ... 
 CASE( MOD( Datevalue( Date_Finished__c ) - datevalue(Date_Received__c) ... 
 CASE( MOD( Datevalue( Date_Finished__c ) - datevalue(Date_Received__c)