Riddles, brain puzzles and mathematical problems

[CarnivorousJelly]

Okay so

Spoiler below!

1. Put your lock on the box, send it to your friend (just your lock on the box)
2. Have your friend put his lock on the box as well, then send it back (both locks on the box)
3. Take your lock off the box and mail the box back (just his lock on the box)

Am I right? :D

[BAndrew]

@Kia

Bingo!

[CarnivorousJelly]

8D I feel smart now >u<

Also, I feel like I should contribute... maybe

A man leaves an $100 dollar bill on his desk and leaves work. When he returns the money is gone. He has three suspects: the cook, the maid, and the mail man. The cook says he put the money under a book on his desk to keep it safe. They check and it is no longer there. The maid says she moved it when she was cleaning to the inside of the book between page 1 and 2. They open the book and look between page number 1 and 2 but it isn't there. The mail guy says he saw it sticking out of the book and to keep it safe he moved it to between page number 2 and 3.

Who stole the money and how do you know?

To clarify: they do not have to check the book a second time to know who stole it.

---

What's the next number in this sequence?

1
11
21
1211
111221
312211

[PutraenusAlivius]

It's the mail guy. Because if he said he moved it between 2 and 3 then when they check it then it should be there.

13112221
Because you counted the amount of numbers in the previous numbers. First one is One "1", and so the second is 11, since it's 1 "1". The third is 21 because in the previous there are Two "1"s. Next is One "1", One "2". And so on.

[CarnivorousJelly]

JAP:

Spoiler below!

Right guy, reasoning's a little off.

You'd get the same result if the mailman had said he moved it between page 44 and 45.

[BAndrew]

The mail guy because he is lying.

Pages NO2 and NO3 are essentially in the same paper (but opposite sides) and therefore they cannot hold anything between.

The other riddle was solved by JAP already

---

In a game show there are three logicians A,B,C. The presenter of the show whispers a (natural) number greater than 0 in the ear of each logician. Then he tells them that the sum of the numbers is 14 and then he asks them if anyone knows all the numbers:

A: I don't know, but I am absolutely sure that the other two have different numbers.
B: I don't know, but I was absolutely sure that everyone had different numbers even before I listened to A.

Then C announces that he knows the number of all three.

How did he figure it out and what were the numbers?

[Froge]

A received an odd number because there is no way for odd + 2n to equal 14.

B received an odd number greater than or equal to 7 (and less than 12). That's because he knew everyone had different numbers even before listening to A, which is only possible if he received 7, 9, or 11 (those are the numbers which result in A and C being different).

Now it's simply a matter of brute forcing the solution:

1. B received 7.
A: 1 -> C = 6
A: 3 -> C = 4
A: 5 -> C = 2

2. B received 9.
A: 1 -> C = 4
A: 3 -> C = 2.

3. B received 11.
A: 1 -> C = 2.

This shows C must have received one of 2, 4, or 6.

Given that C knows what number he received, the only way he can be certain of what the other two are is if he received 6, as that is the only number that has only one combination above matching the statements of A and B.

So A = 1, B = 7, C = 6.

[BAndrew]

@Froge

Excellent!

[Froge]

20 pianists participate in a competition. Out of these 20, 3 played Bach and 5 played Schumann. 6 out of the 20 pianists are chosen at the end of the competition to receive a prize.

What is the probability that, out of the prize winners, at least two played Bach or none played Schumann?

~

/CStards

Suppose you have a set of n numbers, n >= 3. You are given an integer k. Write a program (in C or pseudocode) that calculates the total number of ways 3 numbers can be chosen from the set to add up to k. There may be duplicates in the set, but each number of the set is considered different. No need to do input, just write algorithm and return output.

[Red]

Einstein wrote this riddle last century and said that 98% of the world's population would NOT be able to solve it.

Are you a part of that 98%?


There are 5 houses that are each a different colour.

There is a person of a different nationality in each house.

The 5 owners drink a certain drink. They each smoke a certain brand of cigarettes and also have a certain pet. No owner has the same pet, smokes the same brand of cigarettes nor drinks the same drink.

The question is. "Who has the fish?"


CLUES

1. The British man lives in the red house.

2. The Swedish man has a dog for a pet.

3. The Danish man drinks tea.

4. The green house is to the left of the white house.

5. The owner of the green house drinks coffee.

6. The person that smokes Pall Mall has a bird.

7. The owner of the yellow house smokes Dunhill.

8. The person that lives in the middle house drinks milk.

9. The Norwegian lives in the first house.

10. The person that smokes Blend, lives next to the one that has a cat.

11. The person that has a horse lives next to the one that smokes Dunhill.

12. The one that smokes Bluemaster drinks beer.

13. The German smokes Prince.

14. The Norwegian lives next to a blue house.

15. The person that smokes Blend, has a neighbour that drinks water.