Problems

Age
Difficulty
Found: 2003

The March Hare made three piles of stones of 10, 15, and 20 stones respectively, and invited the Dormouse to play the following game. It is allowed to split any existing pile into two smaller ones in one go. The loser is the one who cannot make a move.

Alice and the Hatter decided to play another game. They found a field with exactly 2016 stones on it. In one go Alice picks 1 or 4 stones, while the Hatter picks 1 or 3 stones. The loser is the one who cannot make a move. Can Alice or the Hatter win irrespective of the other player’s strategy?

Tweedledum and Tweedledee play a game. They have written numbers 1, 2, 3, 4 in a circle. Tweedledum, who makes the first move, can add 1 to any two adjacent numbers; while Tweedledee is allowed to exchange any two adjacent numbers. Tweedledum wins if all the numbers become equal. Can Twedleedee prevent Tweedledum from winning if both must make a move every turn?

While walking through the woods in Wonderland, Alice met three very peculiar hunters. They hunted a hare, which was hiding in one of the vertices of the cube \(ABCDEFGH\).

The three hunters fire simultaneously to hit the vertices of the cube (the hunters are all excellent shooters). If they don’t hit the hare, the hare runs over one of the three adjacent edges to the next vertex and hides there. The hunters ask Alice to help them. They want to shoot the hare firing not more than 4 times, but not sure how to do it. Can you help Alice advise the hunters? (please write four vertex triples to be fired by the hunters).

In the middle of the Dark Forest in Wonderland there is a large square clearing, where a wolf is sitting right is the middle of the square, and four dogs are sitting at the four vertices of the square. The wolf can run inside the square with maximum speed \(v\), while the dogs can run along the edges of the square with the speed \(1.5v\). It is known that the wolf kills a dog if they meet one to one, and two dogs kill the wolf if they overpower it together. Can the wolf escape from that square into the forest?

You have two sticks and matchbox. Each stick takes exactly an hour to burn from one end to the other. The sticks are not identical and do not burn at a constant rate. As a result, two equal lengths of the stick would not necessarily burn in the same amount of time. How would you measure exactly 45 minutes by burning these sticks?

One of your employees insists on being paid daily in gold. You have a gold bar whose value is that of seven days’ salary for this employee. The bar is already segmented into seven equal pieces. If you are allowed to make just two cuts in the bar, and must settle with the employee at the end of each day, how do you do it?

You have a 3-quart bucket, a 5-quart bucket, and an infinite supply of water. How can you measure out exactly 4 quarts?

If you are on a boat and toss a suitcase overboard, will the water level rise or fall?

Suppose you had eight billiard balls, the recruiter began. One of them is slightly heavier, but the only way to tell is by put-ting it on a scale against the others. What’s the fewest number of times you’d have to use the scale to find the heavier ball?