Linux free command meaning

Question

I got some researh to do about linux. One of the questions is the folowing:

'Is it possible that on a running system the output of the command free in the free column is the same for the first 2 rows? How can you force this?'

I googeled around, and I believe I've found the meaning of these values. If I add buffers and cache together, and add that to free, it gives me the value of free for buffers and cache. Which means, the memory that could be used by applications if required so.

So, I suppose it could be that the values could be the same for those 2 rows, it depends on the usage. But, I've no idea how I could