# 23 Fun Brain Teasers That Will Test Your Genius

Flex your mental muscles with these brain-building puzzles.

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!

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

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

Which timepiece has the most moving parts?

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**Answer**: An hourglass

**Answer**: An hourglass

It has thousands of grains of sand!

*Source:* *Forbes*

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

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

What's the reasoning?

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**Answer**: He's playing *Monopoly*

**Answer**: He's playing

*Monopoly*

*Source:* *Forbes*

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

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

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?

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

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

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*

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

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

How can this be?

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

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

*Source: Adapted from Reader's Digest*

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

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

What's the word?

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**Answer**: Short

**Answer**: Short

*Source: Reader's Digest*

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

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

How many people are in the family?

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**Answer**: Nine

**Answer**: Nine

Two parents, six sons, and one daughter!

*Source: Reader's Digest*

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

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

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

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**Answer**: 59 days

**Answer**: 59 days

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*

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**Question**: How many squares are there?

**Question**: How many squares are there?

Hint: Don't forget the big square!

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**Answer**: 40

**Answer**: 40

Count them up here.

*Source: Good Housekeeping*

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

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

Hint: There's a peculiar pattern here.

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**Answer**: 87

**Answer**: 87

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*

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**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.

**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.

What do you light first?

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**Answer**: The match

**Answer**: The match

*Source: Ranker*

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

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

What two coins are in your pocket?

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**Answer**: A nickel and a quarter

**Answer**: A nickel and a quarter

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

*Source: Ranker*

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

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

How can this be?

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**Answer**: His horse's name is Monday

**Answer**: His horse's name is Monday

*Source: Adapted from Ranker*

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

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

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?

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**Answer**: The third door

**Answer**: The third door

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

*Source: Adapted from Ranker*

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

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

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

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**Answer**: The letter M

**Answer**: The letter M

*Source: Quora*

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

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

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

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**Answer**: Halfway

**Answer**: Halfway

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

*Source: Icebreaker Ideas*

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

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

In what place did you finish?

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**Answer**: Second place

**Answer**: Second place

*Source: Good Housekeeping*

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**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.

**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.

How do you measure exactly 7 gallons?

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

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

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*

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

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

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

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**Answer**: ITS

**Answer**: ITS

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

*Source: Icebreaker Ideas*

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

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

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?

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**Answer**: Whatever color your hair is.

**Answer**: Whatever color your hair is.

Remember? You're the bus driver!

*Source: Adapted from Icebreaker Ideas*

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

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

Hint: Look closely at the letters used to spell each word.

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**Answer**: Stop

**Answer**: Stop

All the words are anagrams of each other!

*Source: The 125 Best Brain Teasers of All Time*

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**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?

**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?

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

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**Answer**: "Dirty room"

**Answer**: "Dirty room"

…Which is appropriate in this situation.

*Source: The 125 Best Brain Teasers of All Time*

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

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

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

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

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

…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*

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

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

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

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**Answer**: 11/36

**Answer**: 11/36

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*