Rebellious Randall

You’re waiting to board your flight at the airport with 99 other passengers, each with an assigned seat. All but one of the passengers will gladly sit in their designated seat. The only exception is Randall, a scoundrel who refuses to follow the rules. When he boards, he will choose a random, unoccupied seat.

If a rule-following passenger finds someone in their spot, they will choose another one at a random from the remaining unoccupied seats.

What is the probability that the last person to board the plane will sit in their proper seat?

The randomness stops as soon as someone else sits in Randall’s assigned seat. The chances of this happening range from 1 out of 99 to 1 out of 1 (when only one seat remains).

Thus, the probability of the last person sitting in their own seat can be calculated as 1/99 plus the sum of 2 to 98 of the formula 1 / n × (n + 1), which works out to 0.5, or 50%.

So there’s a 50% chance the last passenger will sit in their own seat thanks to Randall for screwing up order and procedure when boarding an aircraft.

Posted in Brain Teasers

I Stretch The Length of A Football Field

I stretch as far as a football field,
Yet I fit in the palm of your hand.
I will make you bleed if you don’t use me often.
You put me in your mouth but don’t eat me,
Then you throw me away.

What am I?

Floss. It typically comes in 100 yard packs, which fit easily in your hand. If you don’t floss regularly, your gums will bleed. You use floss in your mouth then throw it away when you’re done.

Posted in Riddles
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Against the Rules for You to Play Fair

It’s against the rules for you to play fair,
I always win but you don’t care,
I’ve ruined lives and crushed dreams,
But the allure is too much it seems.

What am I?

A casino. If you use methods to make the odds more fair to you, they kick you out. The house always wins, yet people continue to play. Gambling has ruined countless lives and crushed dreams of making millions, but the hope of winning continues to draw people in.

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Buying Chickens

You must buy 100 chickens for exactly $100, and purchase at least one chicken from each store. The first store charges 5 cents/chicken, the second charges $1/chicken and the third charges $5/chicken. How many chickens should you buy from each store?

80 from store 1 = $4
1 from store 2 = $1
19 from store 3 = $95

Posted in Brain Teasers

The Answer Isn’t 6

What goes in place of the question mark?

1 3 5
2 4 ?

(It’s not 6)

R. It’s a representation of a stick shift, where 1-5 are gears and R represents reverse.

Posted in Brain Teasers

What Digit Does Each Letter Represent?

This is what you know:

1. Each letter represents a different digit from 1 to 9
2. The total of each row is 17.
3. (B × B) + B + F = A
4. C × F = EF (a 2-digit number, not their product)

A B C
D E F

What digit does each letter represent?

A = 7
B = 1
C = 9

D = 8
E = 4
F = 5

A + B + C = 17
D + E + F = 17
B2 + B + F = A
C × F = EF

To begin with, B has to be a 1 or 2 or else A wouldn’t be a single digit. Plug in B = 2, gives you 6 + F = A, meaning F and A can only be (1,7) or (3,9). To get 17, C would have to be 8 or 6, but those values don’t work for C × F = EF. So B must be 1.

2 + F = A means F and A can be (2,4), (3,5), (4,6), (5,7), (6,8) or (7,9). To get 17 on the top row, the only option that leaves C as a single digit is F = 5 and A = 7.

C × F = EF
9 × 5 = 45, so E = 4 and D = 8 to make the second row equal to 17.

Posted in Brain Teasers

A Special Racecar

What is special about the phrase “Race car”?

It’s a palindrome (a word or phrase that’s spelled the same backwards and forwards).

Posted in Brain Teasers

I Cover What Is Real And Hide What Is True

I cover what is real and hide what is true,
But sometimes I bring out the courage in you.

What am I?

A mask. It makes people look different, but can make you feel more powerful than you normally do.

Makeup also works.

Posted in Riddles

Two In A Whole And Four In A Pair

Two in a whole and four in a pair
And six in a trio you see
And eight’s a quartet but what you must get
Is the name that fits just one of me?

A half.

Posted in Riddles

Forever Stuck

I can’t go right,
I can’t go left.

I’m forever stuck going only up and down.

What am I?

An elevator.

Posted in Riddles