Today I used 6 minutes for the 5 examples, 4 were very easy and took around 15 seconds each, but the 5th was quite hard and I used 5 minutes to solve it. It shows a nice motive when a pawn, a knight and a rook can checkmate the king which has 2 pawns which block him.

Can you solve it? Can you post a comment on this post where you write how many minutes did you use?