Riddles and Brain Teasers

Feet on the Hike

A man hiked through the woods with his dog and saw three coyotes, six wolf cubs, seven bunnies, nine squirrels and thirteen chipmunks. How many total feet were there?

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Two. The man has two feet. The rest of the animals have paws.

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No One Can Reach It

It’s red, blue, purple and green, no one can reach it, not even the queen. What is it?

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A rainbow.

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Buckets of Coins

Which would be worth more, a bucket full of nickels or a half bucket of dimes?

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The half bucket of dimes. It might be tempting to say they’d be worth the same, since a nickel is worth half as much as a dime. This would be accurate if they were the same size, but the dime is smaller. Thus more dimes would fit in the same space, resulting in more value for you, you lucky dog.

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What Boys Use, Girls Like and Parents Hate

Boys use it, girls like it, parents hate it. What is this 5-letter word?

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The phone.

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Ten White Man On A Dirt Road

Ten white men standing on a dirt road.
Killed by three eyes as black as night.

What happened?

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Someone bowled a strike. The ten white men are the pins, the dirt road is the bowling alley (it’s not dirt, but it’s the color of dirt, and if it said a smooth wooden alley it wouldn’t be much of a riddle). Three eyes as black as night are the finger holes in the bowling ball.

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The Average of Three

There are three numbers. The first two are 2/3 and 3/4.

What does the third number have to be to make the average of all three be 2?

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4 7/12In order for the average of three numbers to be 2, they must all add up to 6. That gives you this equation:
2/3 + 3/4 + n = 6Solve for n = 55/12, or 4 7/12.

4 7/12

In order for the average of three numbers to be 2, they must all add up to 6. That gives you this equation:
2/3 + 3/4 + n = 6

Solve for n = 55/12, or 4 7/12.

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Largest Product

Using all the digits from 1 to 7, what two numbers have the largest product? For example, 1234 x 567 = 699678 but you can do much better than that.

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742 x 6531 = 4,846,002.A similar problem can be found in L.A. Graham’s Ingenious Mathematical Problems and Methods with a range of 1 to 9, but the principle remains the same – the numbers with the smallest difference produce the largest product. You start out with the highest two digits, 7 and 6, then attach 5 and 4, putting the smaller of the two digits with the larger number, giving you 74 and 65. The next two highest digits are 3 and 2, giving you 742 and 653. Finally, you add the 1 to the lower number. Page 80 has the details of that solution.

742 x 6531 = 4,846,002.

A similar problem can be found in L.A. Graham’s Ingenious Mathematical Problems and Methods with a range of 1 to 9, but the principle remains the same – the numbers with the smallest difference produce the largest product. You start out with the highest two digits, 7 and 6, then attach 5 and 4, putting the smaller of the two digits with the larger number, giving you 74 and 65. The next two highest digits are 3 and 2, giving you 742 and 653. Finally, you add the 1 to the lower number. Page 80 has the details of that solution.

Posted in Brain Teasers