Brain teasers with answers for kids and adults

The Crossing Bridge-brain teaser

Four people need to cross a bridge at night. They only have one torch, and the bridge is too dangerous to cross without it. The bridge can only hold two people at a time. The four people take different times to cross: 1 minute, 2 minutes, 7 minutes, and 10 minutes. How do they all get across in the shortest time possible?

1. The 1-minute and 2-minute people cross first with the torch (2 minutes).
2. The 1-minute person goes back with the torch (1 minute).
3. The 7-minute and 10-minute people cross with the torch (10 minutes).
4. The 2-minute person goes back with the torch (2 minutes).
5. The 1-minute and 2-minute people cross again (2 minutes).
Total time: 17 minutes.

The Hourglass in a Box

A box contains 10 different hourglasses, each with a different sand timer value. You randomly pick one hourglass, turn it over, and let it run out. What is the probability that you picked the hourglass that takes the longest time to empty?

1. Start both hourglasses at the same time. 2. When the 4-minute hourglass runs out, flip it immediately. 3. When the 7-minute hourglass runs out, flip it immediately. 4. When the 4-minute hourglass runs out again (at 8 minutes), there is 1 minute of sand left in the 7-minute hourglass. 5. Let that 1 minute pass. You’ve now measured exactly 9 minutes.

The Poisoned Wine-Brain teaser

You have 1,000 bottles of wine, one of which is poisoned. You have 10 prisoners, and the poison will kill someone exactly 24 hours after they consume it. You need to find the poisoned bottle within 24 hours. How do you do it?

 Label the bottles from 1 to 1,000 and convert each number to binary. Assign each bit to a prisoner (10 bits total). Have each prisoner drink from the bottles where their corresponding bit is a 1. After 24 hours, the prisoners who die reveal which bits are 1 in the binary number of the poisoned bottle.

leep the least-Brain Teasers

During which month do people sleep the least?

Answer: February (there are usually fewer nights in February).

Chicken, Cat and Goat City -Brain Teasers

What is 3/7 chicken, 2/3 cat and 2/4 goat?

Answer: Chicago

Two boxers are in a match scheduled for 12 round-Brain Teasers

Two boxers are in a match scheduled for 12 rounds. (Pure boxing only - no kicking, UFC takedowns, or anything else). One of the boxers gets knocked out after only six rounds, yet no man throws a punch. How is this possible?

Answer: Both boxers are female.

Married many women-Brain Teasers

He has married many women but has never been married. Who is he?

Answer: A preacher

Sliced but stays whole - Brain Teasers

What can be driven although it doesn't have wheels, sliced but stays whole?

Answer: A golf ball

Harder To Catch-Brain Teasers

What is harder to catch the faster you run?

Answer: Your breath

What is the word-Brain Teasers

There is a word in the English language in which the first two letters signify a male, the first three letters signify a female, the first four signify a great man, and the whole word, is a great woman. What is the word?

Answer: Heroine

The Hourglass Puzzle-Brain teaser

You have two hourglasses: one measures 7 minutes and the other measures 4 minutes. How can you measure exactly 9 minutes?

1. Start both hourglasses at the same time.
2. When the 4-minute hourglass runs out, flip it immediately.
3. When the 7-minute hourglass runs out, flip it immediately.
4. When the 4-minute hourglass runs out again (at 8 minutes), there is 1 minute of sand left in the 7-minute hourglass.
5. Let that 1 minute pass. You're now measured exactly 9 minutes.

The Infinite Reflection-brain teaser

• You will see an infinite number of images.
• You will see a total of 10 images.
• You will see only one image.
• You will see two images.

Two parallel mirrors are facing each other, and a candle is placed between them. How many images of the candle will you see?

You will see an infinite number of images. Each mirror reflects the candle and the reflection from the other mirror, creating an endless series of reflections.

Which exit do you pick- Brain Teasers

You're escaping a labyrinth and there are three exits. Exit A leads to an inferno. Exit B leads to an assassin. Exit C leads to a lion that hasn't eaten in 3 years. Which exit do you pick? 

Answer: Exit C. If a lion hasn't eaten in 3 years, it has definitely starved to death.

The Dead elevator-Brain Teasers

An elevator is on the ground floor. There are four people in the elevator, including me. When the elevator reaches the first floor, one person gets out and three people get in. The elevator goes up to the second floor. Two people get out and six people get in. It then goes to the next floor up. No one gets out, but 12 people get in. Halfway up to the next floor, the cable snaps, and the elevator crashes to the floor. Everyone else dies in the lift. How did I survive? 

Answer: I got out on the second floor!

The Infinite Hotel-brain teaser

A hotel with an infinite number of rooms is fully occupied. A new guest arrives. How can the hotel accommodate the new guest without evicting anyone?

Move the guest in room 1 to room 2, the guest in room 2 to room 3, and so on, freeing up room 1 for the new guest. This method works because the hotel has an infinite number of rooms.