March 14 is known as National Pi Day, so many companies and brands are using the event to promote their own products. One of the companies utilizing the celebration is Pizza Hut, and they are willing to give you free pizza if you can win their contest.

The first answer is an integer with ten digits, with all of the digits being distinct from each other. Another clue was that "the number formed by the first n of them is divisible by n for each n from 1 to 10." What do you think is the answer?

The next problem uses a school setting, specifically in a puzzle club that meets every Friday in one of the school's rooms. One of the members said last Friday that a list of numbers was hidden inside an envelope. When they are all combined, the number of the room they are in is revealed.

A girl responded in the second math problem's story.

After the boy talks about the envelope, another girl notes that there is not enough information to know the number of the rooms. She suggested that they should be told about the number of numbers inside the envelope. Moreover, she wanted to know the product of these numbers.

After doing some scribbling, the boy said that the girl would not be able to know all of the numbers and the room's number using the number of the numbers and the product of the hidden numbers. However, the girl said that she now knows the product. So the question is: What is the number of the school rooms the Puzzle Club stays in every Friday?

Finally, this is the third problem in order to win free pizza for 3.14 years.

The person has key-rings that are metal circles. They have a diameter of about two inches, and they are all linked in a weird jumble. Thus, the person could not differentiate one pair of key-rings from another.

However, this person can tell something about the triples.

The triples found in the jumble of key-rings can be identified from each other, even if they cannot be identified as from the left or from the right. So here is the question: "What are the possible numbers of key-rings in this jumble?"

No one has been able to correctly answer the third problem.

Likewise, you do not have to buy anything to join the contest or to claim the prize. Still, this contest is only for people who are at least 18 years old and are in any of the 48 U.S. states identified.