K guys sorry for the fuss and using up your time but the mistake I was making is like you said the initial ball is thrown up, the second one is dropped. So to get the right answer I had to add that one second not subtract it, which did provide correct results. Thanks again for the help.
I am having a problem solving this:
A ball is thrown straight up from the edge of a 20m tall building (ignore air resistance). One second later a second ball is thrown. What must be the initial velocity of the second ball in order for both of them to hit the ground at the same time.
Knowns...