Shared Birthdays

In 2012 a class was divided into 2 groups. Their assignment was to find the names of at least 3 children who were born on the same day from 5 different months of 2011. These were the results:

Group 1
August 20: Oliver, William, and Adam.
January 3: John, Alice, and Ken.
September 7: Bruce, Shane, and Peter.
June 11: April, Patrick, and Bobby.
July 19: Trent, Julie, and Charles.

Group 2
March 1: Karl, Willie, and Patty.
February 29: Blake, Kobe, and Wayne.
December 24: Kyle, Chad, and Zoe.
May 12: Matthew, Manny, and Adrian.
November 20: Greg, Fiona, and Elizabeth.

The members of group 2 got an F on the assignment. Why?

Group 2 failed because 2011 wasn’t a leap year, meaning there was no February 29th.

Posted in Brain Teasers

011 235 Sequence

011 235 813 213 ???

What comes next?

455. The numbers are from the Fibonacci sequence in groups of 3. The next numbers in the series are 34 (the 3 was already used in 213) and 55.

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How Old Is The Shepherd?

There are 125 sheep and 5 dogs in a flock.

How old is the shepherd?

You can’t determine the answer.

I debated adding this riddle because it is less of a riddle and more of an illustration of how kids are (or are not) being taught to think for themselves. But after reading how kids feel the need to make up an answer without understanding why, I thought this could be a good reminder for all of us to exercise our critical thinking skills.

(via Student Voices)

Posted in Riddles

Copying Cassette Tapes

Joe and Andrea want to copy three 60-minute cassette tapes. They have a 2-cassette recorder to copy the tapes, allowing them to copy two tapes at a time. Each side takes 30 minutes to be copied, so two tapes can be copied in an hour and the third will take another hour. Andrea bets Joe she can copy all three tapes in 90 minutes. Does she win the bet?

In the first 30 minutes Andrea copies the A sides of tape 1 and 2.
In the second 30 minutes, she copies tape 1 side B and tape 3 side A (finishing Tape 1).
In the last 30 minutes, she copies tape 2 side B and tape 3 side B.

Posted in Brain Teasers

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

What Has Roots Nobody Sees?

What has roots that nobody sees,
Is taller than trees,
Up, up it goes,
Yet it never grows?

A mountain (from Tolkien)

Posted in Riddles

Three Digits in a Row

On a regular 12-hour digital clock how many times would the same three digits in a row be displayed (e.g. 1:11, 11:12, 12:22) in one day?

34 times. These 17 instances will be visible twice in a 24 hour period.

1:11
2:22
3:33
4:44
5:55
10:00
11:10
11:11
11:12
11:13
11:14
11:15
11:16
11:17
11:18
11:19
12:22

Posted in Brain Teasers

Plane Crash

A plane with 50 passengers crashes and everyone is killed, but there were only 49 bodies. How is this possible?

Two of the passengers were siamese twins.

Posted in Brain Teasers

A Cabin in the Woods

In a small cabin in the woods, two men lay dead. The cabin itself is not burned, but the forest all around is burned to cinders. How did the men die?

It’s the cabin of a plane and the plane crashed.

Posted in Brain Teasers

Born In the Ocean

Born in the ocean,
White as snow,
I’m hidden in water,
Where do I go?

What am I?

Salt. Salt is harvested from seawater, it’s white and it dissolves in water.

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