The Prime Number Riddle
Two hundred people in an auditorium are asked to think of a single digit number from 1 to 9 inclusive and write it down. All those who wrote down a prime number are now asked to leave. Ninety people remain behind in the hall. How many of these are expected to have written down an odd number?
Hint: Remember that 1 is not a prime number.
Those that remain behind must have written {1,4,6,8,9} and from this only {1,9} are odd. The probability of an odd number is thus 2/5.
Expected number of odds is 2/5 * 90 = 36 Did you answer this riddle correctly?
YES NO
Expected number of odds is 2/5 * 90 = 36 Did you answer this riddle correctly?
YES NO
Positive Numbers
Hint:
Who Do You Love?
When I look at her, she smiles at me. When I wink at her, she winks at me. When I kiss her, she kisses me back. When I say I love you, she says it back. Who am I?
Hint:
One Odd Number
Hint:
Only Self-Enumerating Number
Hint:
Four. The number four has four letters, making it self-enumerating. Did you answer this riddle correctly?
YES NO
YES NO
An Odd Number Made Even Riddle
Hint:
Even Number Riddle
Hint:
The Even Number Riddle
Hint:
Not An Even Number Riddle
Hint:
An Odd Number Less Than 74
Hint:
A Number Less Than 80
Hint:
An Even Number Riddle
Hint:
The Same Number Of Ones Riddle
Hint:
Pink Car Riddle
Hint:
Someone You Love Riddle
Hint:
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