Help with some competitive programming problems

Hello fellow programmers,

I am having trouble understanding the “Whack a Money Bag” problem below:

How come you can get 4200 when you can only wack two things on test case 1?
How is the output 3500 for the second example when 2 icons disappear at the same time? I don’t get this…

Also, I don’t understand in general how to set up a way of solving the following “Stamps” problem below. Like what is an algorithm I can use to peel the stamps off one by one?