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
Hats On Your Legs Riddle
Hint:
Sad Nose Riddle
Hint:
A Ninja Under The Weather
Hint:
The Twelve Inch Nose Riddle
Hint:
Ninja At The Doctor
Hint:
The Number Four Be Half Of Five Riddle
Hint:
IV, the Roman numeral for four, which is “half” (two letters) of the word five. Did you answer this riddle correctly?
YES NO
YES NO
Freddy Krueger Wear A Hat Riddle
Hint:
The Correct Number Riddle
Hint:
121
Explanation
Tables consist of squares of the number from 4 to 12.
11^2 = 121. Did you answer this riddle correctly?
YES NO
Explanation
Tables consist of squares of the number from 4 to 12.
11^2 = 121. Did you answer this riddle correctly?
YES NO
Find Those Missing Numbers Riddle
In the attached figure, you can find two missing numbers. Can you analyze the pattern and find those missing numbers?
Hint:
The number missing on the left is 8 and the one on right is 7.
Explanation:
The pattern:
The number in the center of triangle is the square root of the sum of the numbers sitting outside on the corners.
Thus,
10 + 22 + 4 = 36
Square Root of 36 = 6
In the same manner:
10 + 42 + 12 = 64
Square Root of 64 = 8
12 + 22 + 15 = 49
Square Root of 49 = 7 Did you answer this riddle correctly?
YES NO
Explanation:
The pattern:
The number in the center of triangle is the square root of the sum of the numbers sitting outside on the corners.
Thus,
10 + 22 + 4 = 36
Square Root of 36 = 6
In the same manner:
10 + 42 + 12 = 64
Square Root of 64 = 8
12 + 22 + 15 = 49
Square Root of 49 = 7 Did you answer this riddle correctly?
YES NO
I Am A 3 Digit Number Between 400 And 800 Riddle
I am a 3 digit number between 400 and 800. My digits add up to 15. My ten's digit is twice my hundreds digit. What number am i?
Hint:
If A Door Number Fitter Riddle
In a new hotel containing 100 rooms, Tom was hired to paint the numbers from 1-100 on the doors. How many times will Tom have to paint the number 8?
Hint:
The answer is 20. Many people have been guessing anywhere from 9 to 19, but the correct answer is 20. Did you answer this riddle correctly?
YES NO
YES NO
Carpenter Nails Riddle
Hint:
The Red Planet Riddle
I'm named after a Roman God
I'm the fourth planet from the sun
I am known as the red planet
And have two moons rather than one
I'm the fourth planet from the sun
I am known as the red planet
And have two moons rather than one
Hint:
Redmonds Runs Riddle
During a baseball game in Redmond, John was Redmonds lead-off batter. There were no substitutions or changes in the Redmond batting order at all during the nine-inning game. John came to bat in every inning. What is the least number of runs Redmond could have scored?
Hint:
Zero. In the first inning John and the next two batters walk and the next three strike out. In the second inning, the first three walk again, which brings John back to bat. But each runner is caught off base by the pitcher, so John is back at the plate at the start of the third inning. This pattern is now repeated until the game ends with no joy in Redmund, even though the mighty John never once strikes out. Did you answer this riddle correctly?
YES NO
YES NO
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