## October 18, 2013

### The Problem with the Hourglass

Some students have to take a test in 9 minutes. Due to an electromagnetic pulse, every watch has stopped working and we only have two hourglasses to measure time.

These two hourglasses (the only ones we have in the high-school) last for 7’ the first one and 4’ the second one.

How can we measure exactly 9 minutes (neither one second longer, nor shorter) using these hourglasses?

Tip: try to start both hourglasses at the same time. What happens after exactly 4 minutes?

Printable version available.

And we continue with the 90's...

Oasis - "Wonderwall"

## October 4, 2013

### Ismael's Problem

Ismael visits a one-floor castle with 64 rooms connected as described in the image below. He starts in the bathroom (the black square) and since he feels sooooo relieved he wants to visit the 64 rooms using only 15 straight lines.

Would you be able to help Ismael and draw a path for him starting at the balck square and using only 15 different lines ( without removing the pencil from the sheet) so he manages to visit the 64 rooms?

Watch it: You MUST start your trip from the black spot, but you can finish it wherever you want. Notice there’s one missing connection between two towns at the bottom of the drawing.