Welcome to your weekly installment of V’s Riddle Corner. Each Friday evening I’ll provide you with a few riddles to earn you some Tanga Points, and perhaps even a few links to waste some time. The links will tend to be to interesting facts or fun videos, while the puzzles will frequently be based in logic or maths (gasp!). So, without further adieu…

Wastes of Time:

Video to waste some time.

This is just awesome.

Riddle 1: Three overlapping circles are drawn to cut the plane into 7 finite regions, each with 3 circular arcs as its boundary (think of a Venn diagram with 3 circles). 7 coins are placed, 1 in each region, all Heads-Up. Then a game is played, consisting of a sequence of coin flipping steps. At each step a circle is chosen, and one of the following two operations is performed upon all coins in it:

• Operation A: Turn every coin Heads-Up.
• Operation B: Reverse every coin.

The object of the game is to put the coin in the central (inside-most) region Heads-Down, and all other coins Heads-Up. Is this objective accomplishable?

First to post either a sequence of operations that demonstrates the desired outcome or proves that it is impossible receives 15 points.

Riddle 2: How many jellybeans fit in a 1-liter jar? (This is an example of a Fermi problem, and is designed to be calculated using a series of approximations. These problems are named after Enrico Fermi, the inventor of the controlled nuclear reaction, who was also known for answering questions such as “How many piano tuners are there in New York?” using no additional resources but a napkin to write on.)

First to post a good approximation with sound reasoning receives 5 points.

That’s all for today, folks. See you next week!

-V