How to add some particular int values into datetime values

hi , here i want add some particular int values into datetime values

int days =03 int hours=07 int mins=30

and this value already stored in table datetime createdtime=29-12-2015 AM 11:46:57

here how can add days=03 into 29 hours =07 into 11 mins=30 into46

and final output will be datetime updatedtime =01-01-2016 PM 7:16:57

Thanks in Advance..!

Regards cywa