Select random records from a table based on condition

Question

Hi all I have a table which holds data and the table is as follows my requirement is to load some random questions based on the total time against DifId. If against 1 30 minutes was set I need to load question randomly so that total time should be equal to 30.

  Id              Description      Time     DifId
   1                  ABC           1         1
   2                  ABC           5         1
   3                  ABC           9         1
   4                  ABC           10        1
   5                  ABC           10        1
   6                  ABC           2         1