How to find sum total of hours

select convert(varchar(3),SUM(s)/60) + ':' +  convert(varchar(3),SUM(s)%60)
from(
select convert(int,substring('01:25',1,2))*60 + convert(int,substring('01:25',4,2)) s
union all
select convert(int,substring('01:25',1,2))*60 + convert(int,substring('01:25',4,2)) s

) p

DECLARE @Minute1 INT
SET @Minute1 = ( SELECT DATEDIFF(MINUTE,GETDATE(),GETDATE()))
SELECT CAST( @Minute1/60 AS VARCHAR(5))+ ' Hrs' + ':'+ RIGHT('0' + CAST( @Minute1%60 AS VARCHAR(2)), 2)+' Min' AS 'WorkingTime'