How to addd a two times in asp.net using c sharp

Question

i have table like this
 
       ID               Date               time
   Emp1001     4/25/2012           00:02:12

   Emp1001     4/25/2012           00:07:10
    
   Emp1001     4/25/2012           00:08:20

I need to find the total time for the date=4/25/2012

 I need the result like this  totaltime =     00:17:42
 

   i need query.....

thanks in advance....