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.
Riddle: Mr. Taylor has four daughters and each has a brother. In total, how many children does Mr. Taylor have?
Answer: Five children because all of his daughters have the same brother.
Riddle: I possess a halo of water, walls of stone, and a tongue of wood. Long I have stood; what am I?
Riddle: What can run but never walk, have a mouth but never talk, have a head that never weeps, and a bed that never sleeps?
Answer: A river.
Riddle: If an electric train is moving north at 55 mph and the winds blowing east at 70 mph, which way does the smoke blow?
Answer: An electric train doesn’t emit smoke.
Riddle: How many letters are in the alphabet?
Answer: Eleven letters are in “the alphabet”.
Riddle: How can you throw a ball as hard as you can only to have it come back to you without it bouncing off of anything?
Answer: Throw the ball straight into the air.
Riddle: I am the beginning of the end of time and space that surrounds everything and every place. What am I?
Answer: The letter “E”.
Riddle: A man attending his mother’s funeral, sees a woman in another pew, and experiences love at first sight. He tries to find her but has no luck. A few weeks later, he kills his sister. Why does he kill his sister?
Answer: He kills his sister in hopes of seeing the woman at her funeral.
Riddle: People in poverty have this. If you eat this you will die. What is it?
Riddle: A is the brother of B. B is the brother of C. C is the father of D. How is D related to A?
Answer: A is D’s aunt.
Riddle: There is a single-story blue house where everything is blue; the doors, windows, couch, television, kitchen, etc. are blue. What color is the carpet on the stairs in this house?
Answer: There are no stairs, it’s a one-story house.
Riddle: A woman shoots her husband and then holds him underwater for five minutes. Next, she hangs him but right after, they enjoy a nice dinner together. How is this possible?
Answer: She took a photo of her husband and then developed it in her darkroom before dinner.
Riddle: What has roots that no one sees and looms much taller than trees? Up it goes but yet it never grows; what is it?
Riddle: I am laced twice in eternity and always within sight. What could I be?
Answer: The letter “T”.
Riddle: Two fathers and two sons come home from the mall. Yet when they arrive home, only three people get out of the car. How is this possible?
Answer: They are a grandfather, father, and son.
Riddle: What is able to go up a chimney when down but unable to go down a chimney when up?
Answer: An umbrella.
Riddle: A murderer is condemned to death and he has the option to die in one of the following three rooms: a room full of raging fire, a room full of assassins with loaded guns, and a room full of lions who haven’t eaten in years. Which room should he choose?
Answer: The room with the lions because if they haven’t eaten in years then they’re already dead.
Riddle: You’re stuck in a room with no windows, doors, or vents to use to climb out. In the room with you is a light, a mirror, and a log of wood. How do you get out?
Answer: You turn on the light and look into the mirror. In the mirror, you see what you saw so, take the saw and cut the log in half. From there, two halves make a (w)hole and you can use that hole to climb out.
Riddle: What jumps when walking and sits when standing?
Answer: A kangaroo.
Riddle: If you eat me, my sender will eat you. What am I?
Riddle: Steve was murdered on Saturday afternoon. His wife said she was reading. The doorman said he was in the shower. The chef said he was making breakfast. The gardener was pruning hedges. From the information given, who committed the murder?
Answer: The chef because Steve was murdered in the afternoon yet the chef’s alibi was that he was making breakfast.
Riddle: A man is trapped in a room that contains only two exits. The first exit is constructed of magnifying glasses that fry anything that walks through when the sun is out and blazing hot. The second exit includes a fire breathing dragon that is bound and determined to kill. How does the man escape?
Answer: He waits until nighttime and then runs through the first exit.
Riddle: I can shave every day but my beard never changes. What am I?
Answer: A barber.
Riddle: Two girls were born to the same mother, on the same day, at the same time, in the same month, and in the same year, however, they’re not twins. How is this possible?
Answer: The two girls are a part of a set of triplets.
Riddle: Three different doctors said that Paul is their brother yet Paul claims he has no brothers. Who is lying?
Answer: No one is lying because the three doctors are Paul’s sisters.
Riddle: If a plane came crashing down on the border between Canada and America, where are the survivors buried?
Answer: You don’t bury the survivors.
Riddle: How is it possible to drop an egg onto a concrete floor without cracking it?
Answer: Concrete floors won’t crack from an egg dropping on them.
Riddle: I exemplify a rare case where today comes before yesterday. What am I?
Answer: A dictionary.
Riddle: Which English word is the odd one out: Stun, Ton, Evil, Letter, Mood, Bad, Strap, Snap, and Straw?
Answer: Letter as it is the only one that does not spell another word when it’s written backward.
Riddle: Which word has three consecutive double letters?
Riddle: I am born tall and grow short with age. What could I be?
Answer: A pencil.
Riddle: The person who makes it and the person who buys it have no use for it and the person who uses it never sees it or feels it. What is it?
Riddle: My buddies and I were inseparable mates until one by one we were split. My teacher then gave me a smack on the head so off in the corner I sit. What am I?
Answer: A staple.
Riddle: The more these are taken, the more they are left behind. What are they?
Riddle: I eat to live and drink to die. What could I be?
Riddle: A man is looking at a photo of a man on the wall and states, “Brothers and sisters I have none, but this man’s father is my father’s son.” How are the men related?
Answer: The man in the picture is his son.
Riddle: I promise, I offend, I direct, and I fight. What am I?
Answer: A hand.
Riddle: I am a five-letter word. I sound the same when you remove my first letter. I sound the same when you remove my third letter. I sound the same when my last letter is removed and I sound the same when all three are removed. What word am I?
Answer: Empty (empty, emty, emp-t, m-t).
Riddle: What is caught but never thrown?
Answer: A cold.
Riddle: When I am needed by you, you throw me away, but when I’m of no use, you take me back. What am I?
Answer: An anchor.
Riddle: Humans purchase me to eat but then never eat me. What am I?
Answer: Plates and silverware.
Riddle: A man runs away from home, turns left three times, and ends up back at home facing a man in a mask. Who is wearing the mask?
Answer: The man in the mask is a catcher because this is a game of baseball.
Riddle: I fly without wings and cry without eyes. Wherever I lead, darkness follows. What could I be?
Answer: A cloud.
Riddle: First you throw away the outside and cook the inside and then you eat the outside and throw away the inside. What am I?
Answer: Corn on the cob.
Riddle: A man is found murdered in his office and the suspects are Peter, Julie, Jason, Molly, and Brian. There is a calendar in the office with the numbers 6, 4, 9, 10, and 11 written in blood. Who is the killer?
Answer: Jason. The numbers indicate months and the first letter of each month indicated spells the name of the killer.
Riddle: What is it that no one wants but no one wants to lose?
Riddle: The answer is “yes” but the intent means “no”. What is the question?
Answer: “Do you mind?”
Riddle: I am a five-letter word and people eat me. If you remove the first letter I become an energy form. If you remove the first two letters, I am needed to live. Scramble the last three letters and I am a drink. What word am I?
Answer: Wheat (heat, eat, tea).
Riddle: We hurt without moving and poison without touching. We bear truth and lies but are no judged by size. What are we?
Riddle: John and Kelly are long-distance lovers and John has just purchased an engagement ring for Kelly. He wants to mail the ring to her but to make sure it isn’t stolen he wants to put a lock on the package. However, John has locks and Kelly has locks but neither has a key to each other’s locks. Without sending another letter/package, how can they get the ring to Kelly and ensure it isn’t stolen in the process?
Answer: John puts a lock on the package and sends it to Kelly. Kelly puts a lock on the package as well and sends it back to John. Once John has the package again he can remove his lock from it and send it back to Kelly. When Kelly finally gets the package back, only her lock is on it so she can finally open it up.
Riddle: A woman is sitting in her hotel room when someone knocks at the door. She opened the door to find a man she’s never seen before. He says, “Oh I’m sorry, I made a mistake and thought this was my room.” He then ran away and got into an elevator so the woman shut her door and phoned security. What made the woman so suspicious?
Answer: You don’t knock on your own hotel room door.
Riddle: My first is in chocolate but no in ham. My second is in cake and also in jam. My third at tea-time is easily found. Altogether, this is a friend who is often around. What is it?
Answer: A cat; chocolate but not ham (letter “c”), in cake and jam (letter “a”), and tea-time is easily found (letter “t”).
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.
Riddle: A girl has an equal amount of brothers and sisters but each brother only has half as many brothers and sisters. What’s the correct amount of brothers and sisters?
Answer: Four sisters and three brothers.
Riddle: If you’re eight feet away from a door and each move advances you half the distance to the door, how many moves does it take to reach the door?
Answer: The door will never be reached because each move will always only get you half the distance.
Riddle: I have two coins that equal fifteen cents but one of them is not a nickel. What two coins are they?
Answer: A dime and a nickel because one of them is not a nickel but the other one is.
Riddle: The combined age of a father and son is 66 years and the age of the father is the age of the son with reversed digits. How old are they?
Answer: There are three possible answers: 15 and 51, 42 and 24, or 60 and 06.
Riddle: What’s unique about this number: 854, 917, 632?
Answer: It’s the numbers 1 through 9 in alphabetical order.
Riddle: A mother and father have four daughters that each have a brother. How many people are in the family?
Answer: Seven; each of the daughters has the same brother.
Riddle: Which version is correct: 18 plus 19 is 36 or, 18 plus 19 are 36?
Answer: They are both incorrect because 18 + 19 = 37.
Riddle: A man is found hanging dead from his ceiling where the room’s dimensions measure 15 x 15 x 15. However, the man is only 6 feet tall and the rope was only 2 feet long. If there are no windows, the only door was bolted shut from the inside, and there is a puddle of water beneath him, how did he kill himself?
Answer: The man stood on a block of ice and waited for it to melt to be hung.
Riddle: If 9999 = 4, 8888 = 8, 1816 = 3, and 1212 = 0, then what does 1919 = ?
Answer: 1919 = 2. The riddle is about the closed sections of a number. For example, the top of a nine is closed so 9999 has four closed parts. Similarly, the top and bottom of an eight are closed so 8888 has eight closed parts.
Albert Einstein’s Riddle
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?
Riddle: 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.
- The Swede keeps dogs as pets.
- The Dane drinks tea.
- The green house is on the immediate left of the white house.
- The green house’s owner drinks coffee.
- The owner who smokes Pall Mall rears birds.
- The owner of the yellow house smokes Dunhill.
- The owner living in the center house drinks milk.
- The Norwegian lives in the first house.
- The owner who smokes Blends lives next to the one who keeps cats.
- The owner who keeps the horse lives next to the one who smokes Dunhill.
- The owner who smokes Bluemasters drinks beer.
- The German smokes Prince.
- The Norwegian lives next to the blue house.
- The owner who smokes Blends lives next to the one who drinks water
Now, the question is, who owns the fish?
Answer: 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. So, in the end, the correct answer is that 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.
- 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 purpose of 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.” This is because the rule is that the object brought through the Door must have double letters like the two “t”s in “kitten”.
- 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…” Also, 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?