Two Three Four Fifteen

What is the missing number?

2 3 4 15 12
3 4 5 28 20
4 5 6 45 30
5 6 7 66 42
6 7 8 ?? 56

91. To get the number in the fourth column, you add the numbers in column 1 and 2, then multiply by the number in column 2. f(n,m) = (n + m) * m
For example, f(2,3) = (2 + 3) * 3 = 15. Thus f(6,7) = (6 + 7) * 7 = 91

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Three Philosophers Under a Tree

Three philosophers are taking a nap under a tree. While they’re asleep, a small boy smears their noses with red berries. When they awake, they each begin to laugh, thinking the other two are laughing at each other.

But then one philosopher stops laughing, realizing his nose is red too. How did he come to this conclusion?

Let’s call the philosopher’s A, B and C. A reasoned that B was confident his nose wasn’t red. If B saw A’s nose wasn’t red, he would be surprised that C was laughing, because C would have nothing to laugh at. But B wasn’t surprised, therefore, A correctly reasoned his nose was smeared.

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Add More But Weigh Less

The 17 items in your shopping cart weigh 8 pounds. But when your daughter puts in a ball, poster board and yo-yo the shopping cart weighs less. How is that possible?

Your daughter had to get out of the cart to fit the remaining items.

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Make This Addition Problem Correct

This math problem is currently wrong.

11 + 66 + 88 + 96 = 294

How can you make it actually equal 294?

Flip the numbers upside down:

11 + 99 + 88 + 96 = 294

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What Surrounds The World

What surrounds the world, yet dwells within a thimble?

Space.

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A Voice With No Mouth

I am a voice without a mouth, throat or lungs. I know no language but speak in all tongues. What am I?

An echo.

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Add An A But Sounds The Same

What word starts with the letter “I”, becomes another word by adding the letter “A” yet has the same pronunciation?

Isle, Aisle

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A Sign in Japan

This sign was seen in Japan. What does it mean?

A sign seen in Japan

It’s a glass sign containing instructions on a glass door.
It says PULL on one side and PUSH on the opposite side.

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5 25 325 4325

Given

1 = 5
2 = 25
3 = 325
4 = 4325

What does 5 equal?

54325. Rather than being a mathematical solution, the answer is derived by prepending (putting in front of) the value on the left side of the equation with the previous answer. So for 3 you take 25, the previous answer, and put 3 in front, giving you 325. Then you put 4 in front to get 4325 and lastly, put 5 in front to get 54325.

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Cannot Keep Until Given

You cannot keep me until you have given me. What am I?

Your word.

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