When Billy is asked how old he is he replies in two years I will be twice as old as I was 5 years ago?

When was the last time you challenged yourself with a riddle? Riddles are a fun way of testing your problem-solving skills, encouraging you to examine your assumptions, look for alternate meanings, and think more creatively. The brain-flexing value of a good riddle doesn't go away as you grow up; word puzzles like these can help you stay sharp. So read on for 40 hard riddles that will get your gears turning.

1. Winter is coming

Riddle: I belong in the month of December, but not in any other month. I am not a holiday. What am I?

It doesn't have to do with a day or temperature…

Answer: The letter "d"

2. Age-old question

Riddle: When Billy's asked how old he is, he replies, "In two years I will be twice as old as I was five years ago." How old is he?

Just do the math.

Answer: 12 years old

3. Caffeine high

Riddle: George, Helen, and Steve are drinking coffee. Bert, Karen, and Dave are drinking Pepsi. Following this pattern, is Elizabeth drinking coffee or soda?

Pay attention to the vowels.

Answer: Coffee, just like all the other names with two e's. (Those with one "e" drank Pepsi.)

4. Odd word out

Riddle: One of these words does not belong: Which is it and why? Brawl, Carrot, Change, Clover, Proper, Sacred, Stone, Seventy, Swing, Travel.

It's got nothing to do with order they are in

Answer: Carrot. It's the only word that does not become another word when you remove the first and last letters.

5. Saddle up

Riddle: Without a bridle or a saddle, across a thing I ride a-straddle. And those I ride, by help of me, though almost blind, are made to see. What am I?

Look closely and the answer should come into focus

Answer: Eye glasses

6. Floating in the breeze

Riddle: White bird, featherless. Flying out of paradise. Flying over sea and land. Dying in my hand. What is it?

Think you got it? You're getting colder…

Answer: A snowflake

7. Hot tempered

Riddle: My thunder comes before the lightning. My lightning comes before the clouds. My rain dries all the land it touches. What am I?

We could also add that you don't want to be near me when I blow my top.

Answer: A volcano

8. An odd body

Riddle: Who has a neck and no head, two arms and no hands?

It can look pretty funny or wrinkly.

Answer: A shirt

9. Think smaller

Riddle: I'm everywhere and a part of everyone. I am at the end of space and time and existence itself. What am I?

Think more literal than metaphysical.

Answer: The letter "e"

10. A busy and buzzy day

Riddle: Who spends the day at the window, goes to the table for meals, and hides at night?

He's also not a particularly welcome dinner guest.

Answer: A fly

11. Getting personal

Riddle: This belongs to you, but everyone else uses it.

Don't get tripped up thinking this is an actual object…

Answer: Your name

12. Wooden delivery

Riddle: I come from a mine and am surrounded by wood. I help others to express themselves. What am I?

Thanks to texting and email, I don't get used as much as I used to.

Answer: Pencil lead

13. A common mistake

Riddle: Which word in the dictionary is always spelled incorrectly?

The answer is right there in the question.

Answer: "Incorrectly"

14. Where in the world

Riddle: I have cities, but not houses. I have mountains, but no trees. I have coasts, but no sand. What am I?

Think "bigger picture" with this one.

Answer: A map

15. Read all about it

Riddle: What English word has three consecutive double letters?

This word actually refers to someone who loves numbers.

Answer: Bookkeeper

16. Hard to see

Riddle: You're in a dark room with a candle, a wood stove, and a gas lamp. You only have one match, so what do you light first?

This one is obvious when you know what to look for.

Answer: The match

17. An illuminating question

Riddle: You measure my life in hours, and I serve you by expiring. I'm quick when I'm thin and slow when I'm fat. The wind is my enemy.

"Quick" does not mean that it is moving toward you.

Answer: A candle

18. Sail away

Riddle: You see a boat filled with people. It has not sunk, but when you look again you don't see a single person on the boat. Why?

Focus on the word "single" to figure out the answer to this one.

Answer: All the passengers are married.

19. Don't know what you got til it's gone

Riddle: What gets bigger the more you take away?

Good luck digging yourself out of this one.

Answer: A hole

20. To have and to hold

Riddle: What can you hold in your right hand but never in your left?

The answer is right there in front of you.

Answer: Your left hand

21. Key question

Riddle: I have keys but no locks. I have space but no room. You can enter, but you can't go outside. What am I?

If you're like most modern workers, you spend a lot of time on this during the typical day.

Answer: A computer keyboard

22. Well worn

Riddle: It's best to put this coat on wet.

This one's easy once you realize it's not about an item of clothing.

Answer: A coat of paint

23. Gotta hand it to you

Riddle: What has four fingers and a thumb but isn't alive?

No, the answer is not "hand."

Answer: A glove

24. Springtime

Riddle: What is seen in the middle of March and April that can't be seen at the beginning or end of either month?

The trick here is that this answer has nothing to do with the time of year when the months fall, but the words themselves.

Answer: The letter "R"

25. Violent imagery

Riddle: A woman shoots her husband. She plunges him underwater for several minutes, then hangs him. Right after, they enjoy a lovely dinner. What happened?

When we say "him," we aren't actually referring to a person.

Answer: She took a picture of him and developed it in her dark room.

26. Family time

Riddle: A is the brother of B. B is the brother of C. C is the father of D. So how is D related to A?ae0fcc31ae342fd3a1346ebb1f342fcb

Don't let all this talk of "brothers" and "father" might get you stuck thinking about male relatives.

Answer: A is D's aunt.

27. A good cut

Riddle: A butcher stands six feet and one inch tall and wears size 12 shoes. What does he weigh?

Pay close attention to the phrasing of the question—there's a reason it didn't ask, "How much does he weigh?"

Answer: Meat

28. A filthy question

Riddle: How much dirt is in a hole that measures four feet by four feet by five feet?

Don't let the specific numbers fool you—the answer would be the same no matter what the hole measured.

Answer: None

29. Looking for inspiration

Riddle: What word in the English language fulfills all the following criteria: The first two letters signify a male, the first three letters signify a female, the first four letters signify a great person, while the entire word signifies a great woman.

Think Wonder Woman…

Answer: Heroine

30. Some find it blissful

Riddle: What disappears the moment you say its name?

It's also something you can "break" the moment you speak.

Answer: Silence

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Riddle: I speak without a mouth and hear without ears. I have no body, but I come alive with wind. What am I?

Don't let the description of body parts throw you—the answer is definitely not a person or animal. Focus more on the "wind" to get to the answer.

Answer: An echo

32. One after another

Riddle: What are the next three letters in this combination? OTTFFSS.

To figure this one out, think less about letters than numbers.

Answer: ENT. Each letter is the first letter of a number beginning with One. So what comes after six and seven? Eight, nine, and ten.

33. Number crunching

Riddle: How is seven different from the rest of the numbers between one and ten?

Sort of the reverse of the previous riddle, this one tricks you by making you think that it's a numbers question, when it's actually about words.

Answer: Seven is the only one with two syllables.

34. Time is on my side

Riddle: What comes once in a minute, twice in a moment, but never in a thousand years?

Think less about the meaning of the words than the words themselves.

Answer: The letter "m"

35. Psst…you'll never guess it

Riddle: If you have me, you want to share me. If you share me, you don't have me. What am I?

It's something you share with friends.

Answer: A secret

36. Signed, sealed, delivered

Riddle: I have only two words but thousands of letters. What am I?

"Letters" is the important clue to focus on here.

Answer: Post office

Riddle: First you eat me, then you get eaten. What am I?

The "you" in this instance is an animal.

Answer: A fishhook

38. Numerous possibilities

Riddle: Turn me on my side, and I am everything. Cut me in half and I am nothing. What am I?

Consider the concept of shape.

Answer: The number eight

39. World traveler

Riddle: What can travel all around the world while remaining stuck in a corner?

It might also find itself in a collection.

Answer: A stamp

40. Headless

Riddle: I have a neck and no head, two arms and no hands? What am I?

C'mon, you know this one by now.

Answer: A shirt