Calculate Total based on Hard code values in SSRS

HI Experts,

I would like to calculate the total for Standard time Sec Column. 

This is my screen shot.

Note: the No. of days should vary based on filters.Now we able to see 7 days, some times you would see 8,10,20 days that depends on the date range you are selected.

So I should  have to calculate total for the StandardTimesec column. Can anyone guide me please how to write the expression?

Thanks,

RK