These are some of the hardest riddles for ages 18+. These riddles are best for those with keen math skills, science skills, and a general IQ of 90 to 110. Some of these hard riddles might be complicated for kids, though it doesn’t hurt to challenge their critical thinking skills. These will be more fitting–and maybe even fun–for adults who want to elevate their critical thinking and problem-solving skills.
Start off with the tricky riddles and then ease into the more challenging riddles. You’ll use logical thinking and problem-solving skills to figure out the answers. The more difficult puzzles have a clue or a hint to help solve the answer. Get started by trying to solve the first riddle and puzzle below.
Mr. Smith has four daughters. Each of his daughters has a brother. How many children does Mr. Smith have?
Mr. Smith has 5 children because his daughters all have the same brother.
Halo of water, tongue of wood, walls of stone, long I stood. What am I?
What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?
An electric train is moving north at 100mph and a wind is blowing to the west at 10mph. Which way does the smoke blow?
An electric train doesn’t emit smoke.
How many letters are in the alphabet?
There are 11 letters in “the alphabet”.
How can you throw a ball as hard as you can, to only have it come back to you, even if it doesn’t bounce off anything?
Throw the ball straight up in the air.
I’m the beginning of the end and the end of time and space. I am in everything and surround every place. What am I?
The letter “E”.
Poor people have it. Rich people need it. If you eat it you die. What is it?
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?
A is D’s aunt.
There is a single-story blue house and everything is blue, the doors are blue, the windows are blue and the TV is blue. What color is the staircase?
There are no stairs. It’s a one-story house.
A woman shoots her husband, then holds him underwater for five minutes. Next, she hangs him. Right after, they enjoy a lovely dinner. Explain.
She took a picture of him and developed it in her darkroom.
What has roots as nobody sees, is taller than trees. Up, up, up it goes, and yet never grows?
I occur twice in eternity, and I’m always within sight. What am I?
The letter “T”
Two fathers and two sons are in a car, yet there are only three people in the car. How?
They are a grandfather, father, and son.
What can go up a chimney down, but can’t go down a chimney up?
A murderer is condemned to death. He has to choose between three rooms: the first is full of raging fires; the second, assassins with loaded guns, and the third, with lions who haven’t eaten in years. Which room is the safest?
The room with the lions because the lions are already dead.
What jumps when it walks and sits when it stands?
If you eat me, my sender will eat you. What am I?
A fish hook!
A man is trapped in a room. The room has only two possible exits: two doors. Through the first door, there is a room constructed from magnifying glasses. The blazing hot sun instantly fries anything or anyone that enters. Through the second door, there is a fire-breathing dragon. How does the man escape?
He waits until night time and then goes through the first door.
I can shave everyday but my beard stays the same. What am I?
Two girls were born to the same mother, on the same day, at the same time, in the same month and year, and yet they’re not twins. How can this be?
The two babies are two of a set of triplets.
Three doctors said that Robert is their brother. Robert says he has no brothers. Who’s lying?
No one is lying – Robert has 3 sisters who all happen to be doctors.
A plane crashed between the border of Canada and America. Where do you bury the survivors?
They are survivors, you don’t bury them.
How can you drop a raw egg on the concrete floor without cracking it?
The egg won’t crack the concrete floor!
I’m a rare case where today comes before yesterday. What am I?
Which English word is the odd one out – Stun, Ton, Evil, Letter, Mood, Bad, Snap, Straw?
What word has three consecutive double letters? (Clue: it’s a compound word.)
The person who makes it has no need of it; the person who buys it has no use for it. The person who uses it can neither see nor feel it. What is it?
My buddies and I were inseparable mates
Til one by one were we split
My teacher, she gave me a smack on the pate
And off in the corner I sit.
Admittedly still I’m not hitting the books
Though now I’m hugging a tree
I guess in the end it’s not bad as it looks
I went from a C to a B…
A man is looking at a picture of a man on the wall and states, “Brothers and sisters I have none, but this man’s father is my father’s son.” Who is the man in the picture in relation to the man looking at the picture?
The man in the picture is his son (the man’s son). Since he doesn’t have any brothers or sisters, the statement my father’s son is himself. A shortened version would be this man’s father is myself, so he is the father of the man in the picture.
I promise, I do, I offend, I direct and I fight. What am I?
I am a five-letter word. I sound the same when you remove my first letter. I sound the same when you remove my 3rd letter. I sound the same when you remove my last letter, and I sound the same when you remove all three. Which word am I?
Empty, mpty, emty, emp-t, m t.
What when needed, is thrown away; when not needed, is carried back?
A man runs away from home. He turns left and keeps running. After some time he turns left again and keeps running. He later turns left once more and runs back home. Who was the man in the mask?
The catcher (in a baseball game).
Throw away the outside and cook the inside, then eat the outside and throw away the inside. What am I?
Corn on the cob. One throws away the husk, cook and eat the kernels, and then throw away the cob.
A man is found murdered in his office. The suspects are Peter, Julie, Jason, Molly, and Brian. In the office is a calendar with the numbers 6,4,9,10,11 written in blood. Who is the killer?
Jason is the killer. The numbers indicate months and the first letter of each month spells the name of the murderer, e.g. the 6th month is June and the first letter of June is J, the 4th month is April and the first letter of April is a, and so on.
What is it that no one wants, but no one wants to lose?
The answer I give is yes, but what I mean is no. What was the question?
“Do you mind?”
I am a word of 5 letters and people eat me. If you remove the first letter, I become a form of energy. Remove the first two and I’m needed to live. Scramble the last 3 and you can drink me. What am I?
Wheat, heat, eat, tea
We hurt without moving and poison without touching. We bear truth and lies but are not judged by size. What are we?
Tim and Mel are long-distance lovers. Tim has just purchased an engagement ring for Mel and wants to mail it to her. Unfortunately, the only way to ensure the ring will be received is to place a lock on the package. Tim has locks and Mel has locks but neither have keys for each others’ locks. How can they ensure the ring isn’t stolen?
Tim places a lock on the package and sends it to Mel. Mel places one of her locks on the package and sends it back to Tim. Tim removes his lock and sends the package back to Mel.
A woman is sitting in her hotel room when there is a knock at the door. She opened the door to see a man whom she had never seen before. He said, “Oh I’m sorry. I have made a mistake. I thought this was my room.” He then went down the corridor and in the elevator. The woman went back into her room and phoned security. What made the woman so suspicious of this man?
You don’t knock on your own hotel room door!
My first is in chocolate but not in ham, my second’s in cake and also in jam, my third at tea-time is easily found, my whole is a friend who’s often around. What am I?
If you’re a math teacher hoping to get your students to enjoy the subject, try challenging them with a tough riddle or math puzzle. It’s a fun way for the kids to challenge their lateral thinking and problem-solving abilities and maybe even start to like the subject…
A girl has as many brothers as sisters, but each brother has only half as many brothers as sisters. How many brothers and sisters are there in the family?
Four sisters and three brothers.
If you’re 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?
You will never reach the door, it will always be half the distance, no matter how small.
I have two coins equaling fifteen cents. One of them is not a nickel. What are the two coins?
A dime and a nickel. One of the coins is not a nickel, but the other one is.
The combined age of a father and son is 66 years. The age of the father is the age of the son, but with the digits reversed. How old are they?
51 and 15 or 42 and 24 or 60 and 6.
What is special about the number 854,917,632?
It’s the numbers from 1-9 in alphabetical order.
Mom and dad have four daughters, and each daughter has one brother. How many people are in the family?
Which is correct: 18 plus 19 is 36. Or 18 plus 19 are 36?
Actually, both are incorrect – 18 plus 19 is 37!
A man is found hanging dead from the ceiling of a room. The room’s dimensions are 15 x 15 x 15. The man is only 6ft tall and the rope was only 2ft long. There are no windows and only one door into the room. The door is bolted shut from the inside and there is a puddle of water under the man. How did he kill himself?
The man stood on a block of ice.
If 9999=4, 8888=8, 1816=6, 1212=0, then 1919=? (Clue: Closed areas.)
9999 has 4 closed areas (the top of the ‘9’).8888 has 8 closed areas (the top and bottom parts of 8 and there are no other digits). 1816 has 3 closed areas (top and bottom of 8 and bottom of 6, and it has 2 other digits (3 * 2 = 6)). 1212 has 0 closed areas, (0 * 4 = 0).
Now, if you’re really up for a challenge, here is Albert Einstein’s riddle, one that is believed to be developed when he was young. The best way to solve this brain teaser is through logic and deductive reasoning.
Think you can solve it?
Five houses painted five different colors stand in a row. One person of a different nationality lives in each house. The five homeowners all drink some type of beverage, smoke a certain cigar brand, and have a certain kind of pet. But none of the owners drink the same beverage, smoke the same type of cigar, or have the same pet.
Here are the clues:
- The Brit lives in the red house.
2. The Swede keeps dogs as pets.
3. The Dane drinks tea.
4. The green house is on the immediate left of the white house.
5. The green house’s owner drinks coffee.
6. The owner who smokes Pall Mall rears birds.
7. The owner of the yellow house smokes Dunhill.
8. The owner living in the center house drinks milk.
9. The Norwegian lives in the first house.
10. The owner who smokes Blends lives next to the one who keeps cats.
11. The owner who keeps the horse lives next to the one who smokes Dunhill.
12. The owner who smokes Bluemasters drinks beer.
13. The German smokes Prince.
14. The Norwegian lives next to the blue house.
15. The owner who smokes Blends lives next to the one who drinks water.
Now, the question is…Who owns the fish?
Think you figured out the correct answer to this riddle? Well, here it is:
The German in house #4 owns the fish.
BONUS: A Fun Riddle Game
This riddle wordplay game is known as the Green Glass Door. It can be played at parties, in classrooms, and just as a fun icebreaker. If you’re a teacher looking to challenge your kids in the classroom, try out this entertaining logic puzzle to test their knowledge about compound words. (You know, those combined words, like sunflower [sun and flower] or moonlight [moon and light] or railroad [rail and road]). You’ll be sure to stump but also entertain your students with this tricky, yet funny riddle game:
Here’s how to play:
Tell the group that you are going to take something through a Green Glass Door and that everyone else must also do the same in turn. The reason for the game is to determine what can be brought through the Green Glass Door.
Go first and say the following: “I can bring a kitten through the Green Glass Door, but I cannot bring a cat.”
The object must have double letters, either double vowels or double consonants.
If a player tries to take an object through the Green Glass Door that doesn’t have a double letter, say “You cannot take that through the Green Glass Door. You must take…”
If a player believes they know the pattern, the game leader should question them and have them give an example rather than state the answer.
Were those easy riddles?