What Do These Dates Have In Common?

What do these dates have in common?

15 February 1984
2 July 1983
16 December 1983

They all fall in the middle.
15 February was the middle of February (1984 being a leap year).
2 July was the middle day of the year 1983.
And 16 December was the middle of December.

Posted in Brain Teasers

A Neighborly Argument

Two of your neighbors were arguing about if the first man’s peacock laid an egg in the seconds man’s garden, who would own the egg. They asked you to solve their dilemma. What would you tell them?

Peahens lay eggs. Peacocks are males.

Posted in Brain Teasers

Marcus’ Strange Age

Marcus was 15 years old in 2010. In 2015 he was only 10 years old. How is this possible?

The years are B.C., so 2015 came before 2010.

Posted in Brain Teasers

What Times Seven Is All Fours?

What is the smallest integer that is all 4s when multiplied by 7?

63,492 × 7 = 444,444

Posted in Brain Teasers

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

The Truck and the Plane

A delivery truck from the post office is sent to the airport to meet a cargo plane at its planned arrival time. The plane lands ahead of schedule and its contents are brought toward the post office by bicycle. After a half hour, the bicycle meets the truck and the mail is transferred.

The truck returns from the post office 20 minutes early. How early did the plane arrive? (Assume all transactions are instantaneous)

The delivery truck arrived back 20 minutes early, so it would have taken 20 minutes to go from where it met the bicycle to get to the airport and back. Therefore, the bicycle and truck met when the truck was 10 minutes from the airport. Adding those 10 minutes to the 30 minutes the truck had already driven to meet the bicycle means the plane arrived 40 minutes ahead of schedule.

Posted in Brain Teasers

What Goes Up But Never Comes Down?

What goes up but never comes down?

Your age.

Posted in Riddles

I Have Hundreds of Legs

I have hundreds of legs but I can only lean,
You make me feel dirty so you can feel clean.

What am I?

A broom.

Posted in Riddles
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Speaks Without Words

What is it that speaks without any words?
And can be loudly and distinctly heard?
Will drive away friend, and foe alike.
And is enough to make a stolid man’s face alight?

Flatulence.

Posted in Riddles

Stocking the Shelves

Alfred and Bill are clerks at the local grocery store. Alfred can stock a shelf in 20 minutes, but Bill is new and takes 30 minutes. How long would it take for them to stock a shelf together?

Working together they can stock a shelf at a rate of 1/20 + 1/30 (or 5/60) per minute. They’ll finish in 12 minutes

Posted in Brain Teasers