Question: how to calculate business hours in salesforce?
Answer: IF(
datetime_1 - datetime_2 > 0 ,
TEXT( FLOOR( datetime_1 - datetime_2 ) ) & " days "
& TEXT( FLOOR( MOD( (datetime_1 - datetime_2 ) * 24, 24 ) ) ) & " hours "
& TEXT( ROUND( MOD( (datetime_1 - datetime_2 ) * 24 * 60, 60 ), 0 ) ) & " minutes",
""
)