hi i need help , i tried some formulas around but im not getting the results

i want to count the working hours from date 1 to date 2 with subtracting non working days (weekends) and non working hours. working hours in a day should be 9 hours, no specific start hour or end hour

start day and time
6/4/2010 11:37

end day and time

6/9/2010 16:10

results should be :
31:32:28

please can someone help me out over here, i need this to be done for work