Puzzle 1
At the recent BrainBashers code-breaking convention, Billie Brisk won the speed contest.
The following sentence was deciphered in a record time of 123 seconds.
What was the well-known saying and how has it been encrypted?
MOOT CYNA SKOO IOPS EHTL TORB YCBH
Puzzle Copyright © Kevin Stone
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Hint
The first word begins with T.
Answer
Too many cooks spoil the broth.
Reasoning
The saying has been broken down into blocks of 4, the last block has been filled with dummy letters. Each block has then been reversed.
Double-Checking
Start with:
TOO MANY COOKS SPOIL THE BROTH
Group together:
TOOMANYCOOKSSPOILTHEBROTH
Split into groups of 4 letters:
TOOM ANYC OOKS SPOI LTHE BROT H
Add 3 random characters:
TOOM ANYC OOKS SPOI LTHE BROT HBCY
Reverse each group of 4 letters:
MOOT CYNA SKOO IOPS EHTL TORB YCBH
Puzzle 2
Which is larger:
the tenth root of 10, or the cube root of 2?
Puzzle Copyright © Kevin Stone
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Hint
You don't need to use a calculator.
Answer
Cube root of 2.
Reasoning
We could use a calculator to see that the tenth root of 10 = 1.2589 and the cube root of 2 = 1.2599.
But, if you've not got your calculator handy...
We have:
101/10 vs 21/3
Raise each to the power of 30 (since 10 x 3 = 30) to give:
(101/10)30 vs (21/3)30
101/10 x 30 vs 21/3 x 30
103 vs 210
1000 vs 1024
Therefore, the cube root of 2 is larger.
Puzzle 3
What is the next number in this sequence:
100 365 24 60 {?}
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Hint
The answers are related to time.
Answer
60.
The numbers represent 100 years in a century, 365 days in a year, 24 hours in a day, 60 minutes in an hour and 60 seconds in an minute.
Puzzle 4
What is the 20th prime number?
2, 3, 5, 7, ...
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Hint
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, ...
Answer
71.
The first twenty prime numbers are: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71.
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