23 Fun Brain Teasers That Will Test Your Genius

Flex your mental muscles with these brain-building puzzles.

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Although it isn't actually a muscle, your brain has a lot in common with your biceps: When you exercise it, it gets stronger. Because your brain can't run, do yoga, or lift weights, however, you've got to find a different way to keep it fit—and brain teasers are just the thing. In fact, in one 2018 study published in the Journal of the American Geriatrics Society, people who did brain teasers and other types of "brain training" reported improvements in mental sharpness and in their ability to execute mundane tasks, like cooking and accounting. Want to see for yourself? Take a stab at the following puzzles that'll test your genius. At the very least, we can guarantee they'll keep you entertained!

Question: Among timepieces, sundials have the fewest moving parts…

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Which timepiece has the most moving parts?

Answer: An hourglass

Hourglass
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It has thousands of grains of sand!

Source: Forbes

Question: Upon taking his car to a hotel, a man immediately declares bankruptcy.

Old fashioned car parked outside Hotel de Paris in Monte Carlo
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What's the reasoning?

Answer: He's playing Monopoly

Monopoly
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Source: Forbes

Question: A man is stranded on a riverbank with a wolf, a sheep, and a cabbage…

Man stand up paddling on a raft down a river
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He finds a raft with which to cross the river, but the raft can fit only himself and either the wolf, the sheep, or the cabbage. If he leaves the wolf with the sheep, the wolf will eat the sheep. If he leaves the sheep with the cabbage, the sheep will eat the cabbage. How can the man cross the river with the wolf, the sheep, and the cabbage?

Answer: The man crosses first with the sheep, leaving the wolf with the cabbage…

Sheep looking over the terrain water below
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He returns alone, then crosses with the wolf, leaving the cabbage behind. He leaves the wolf alone and returns with the sheep. The man leaves the sheep and crosses with the cabbage. He leaves the cabbage with the wolf and crosses one last time, returning with the sheep. Finally, all four are safe on the other side of the river.

Source: Adapted from Icebreaker Ideas

Question: A woman is born in 2020, but dies in 1995.

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How can this be?

Answer: The woman was born in 2020 B.C.

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Source: Adapted from Reader's Digest

Question: This five-letter word becomes shorter when you add two letters to it.

Young woman using computer laptop with hand on chin thinking about question, pensive expression. Smiling with thoughtful face. Doubt concept.
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What's the word?

Answer: Short

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Source: Reader's Digest

Question: A family has two parents and six sons. Each of the sons has one sister.

Mim sitting on couch overwhelmed by a lot of kids
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How many people are in the family?

Answer: Nine

7 kids holding hands in a field at sunset silhouette
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Two parents, six sons, and one daughter!

Source: Reader's Digest

Question: The water level in a reservoir is low, but doubles every day. It takes 60 days to fill the reservoir.

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How long does it take for the reservoir to become half full?

Answer: 59 days

Reservoir sunset
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Your first instinct probably is to divide 60 in half. But if the water level doubles every day, the reservoir on any given day was half the size the day prior. If the reservoir is full on day 60, that means it was half full on day 59—not on day 30.

Source: Adapted from Good Housekeeping

Question: How many squares are there?

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Puzzles and Riddles

Hint: Don't forget the big square!

Answer: 40

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Count them up here.

Source: Good Housekeeping

Question: In what number parking spot is the car parked?

Guess which spot the car is parked in
Puzzler's World

Hint: There's a peculiar pattern here.

Answer: 87

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Once you realize that you're reading the numbers upside-down, you'll see that the car is parked in spot No. 87.

Source: Ranker

Question: You're in a cabin with no electricity. Come nightfall, you have a candle, a wood stove, and a gas lamp, but only one match.

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What do you light first?

Answer: The match

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Source: Ranker

Question: In your pocket are two newly minted U.S. coins with a sum of 30 cents. One isn't a nickel.

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What two coins are in your pocket?

Answer: A nickel and a quarter

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Only one of the coins is excluded from being a nickel.

Source: Ranker

Question: A cowboy gallops into town on Monday, stays for two days, and leaves town on Monday.

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How can this be?

Answer: His horse's name is Monday

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Source: Adapted from Ranker

Question: You're stuck in a room with three exits…

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One exit leads to a pit of venomous snakes. Another exit leads to a lethal inferno. The third and final exit leads to a pool of great white sharks that haven't eaten for six months. Which door should you choose?

Answer: The third door

Multiple great white sharks swimming
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Great white sharks typically can only live three months without food.

Source: Adapted from Ranker

Question: What can be found once in a minute, twice in a moment, and never in a thousand years?

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Hint: Look closely and you'll see the answer.

Answer: The letter M

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Source: Quora

Question: How far can a squirrel run into the woods?

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Hint: Nope, he's not a particularly fast squirrel.

Answer: Halfway

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After that, he's running back out of the woods.

Source: Icebreaker Ideas

Question: You're running a race. Before you cross the finish line, you pass the person who is in second place.

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In what place did you finish?

Answer: Second place

People running through the finish line of a race
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Source: Good Housekeeping

Question: You need 7 gallons of water, but you only have two jugs with which to measure: a 5-gallon jug and a 3-gallon jug.

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How do you measure exactly 7 gallons?

Answer: First, you fill the 5-gallon jug from the faucet…

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You then pour the contents of the 5-gallon jug into the 3-gallon jug until the 3-gallon jug is full. That leaves 2 gallons of water in the 5-gallon jug. Next, you dump out the 3-gallon jug and pour the 2 gallons of water from the 5-gallon jug into the empty 3-gallon jug. Finally, fill the 5-gallon jug from the faucet a second time; those 5 gallons plus the 2 gallons in the 3-gallon jug equals 7 gallons.

Source: Icebreaker Ideas

Question: What are the next three letters in the sequence WATNTL?

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Hint: The answer's right there in the question.

Answer: ITS

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The complete sequence is the first letter of every word in the sentence.

Source: Icebreaker Ideas

Question: You're driving a bus. The bus starts out empty…

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At the first stop, two people get on. At the second stop, eight people get on and one person gets off. At the third stop, three people get on and five people get off. The bus is yellow, but what color is the bus driver's hair?

Answer: Whatever color your hair is.

Young woman driving a public transportation bus
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Remember? You're the bus driver!

Source: Adapted from Icebreaker Ideas

Question: Which word logically comes next in this sequence? Spots, tops, pots, opts…

Pots hanging near kitchen window
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Hint: Look closely at the letters used to spell each word.

Answer: Stop

Stop sign against blue sky with clouds
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All the words are anagrams of each other!

Source: The 125 Best Brain Teasers of All Time

Question: The letters of the word dormitory can be rearranged to produce a two-word phrase that describes a typical dormitory. What is that phrase?

Girl studying in dorm room
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Hint: Think about the words you'd use to describe your child's dorm room…

Answer: "Dirty room"

Messy dorm room
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…Which is appropriate in this situation.

Source: The 125 Best Brain Teasers of All Time

Question: I have seven billiard balls, one of which weighs less than the other six. Otherwise, they all look exactly the same…

Man shooting pool billiard
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How can I identify the one that weighs less on a balance scale, using that scale no more than two times?

Answer: Separate six of the seven balls into two piles of three and weigh them against each other…

balance scale

…If the scale balances, then you know that the heavier ball is the seventh remaining ball. If the scale isn't balanced, then take the heavier side and weigh any two of those three balls against one another. Either the scale will reveal that one of those two balls is the heavier one, or it will balance and reveal that the remaining ball is your culprit.

Source: The 125 Best Brain Teasers of All Time

Question: What is the probability of obtaining either a 6 or a 7 when throwing a pair of dice?

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Bet you're wishing you paid attention in fifth grade math, huh?

Answer: 11/36

Chart for dice outcome
The 125 Best Brain Teasers of All Time

To solve this one,  start by listing the number of ways to throw either a 6 or a 7. There are 36 possible throws of two dice, because each of the six faces of the first die is matched with any of the six faces of the second one. Of these 36 possible throws, 11 produce either a 6 or a 7. Therefore, the probability of throwing either a 6 or a 7 is 11/36.

Source: The 125 Best Brain Teasers of All Time

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