Probability That Both Children Are Girls

Walking down the street one day, I met a woman strolling with her daughter. “What a lovely child,” I remarked. “In fact, I have a younger child as well,” she replied.

What is the probability that both of her children are girls?

1/2 probability. This has been know to cause raging debates and is known as one of the variations of the Boy or Girl paradox. This variation is more straightforward because knowing the position of the child leaves only two possibilities – the other child is a boy or a girl, each of which have a 1/2 probability.

Another variation of this can be found here.

Posted in Brain Teasers

Three Items for $100

Bill buys three items at the store for exactly $100. The second item costs half as much as the first item, and the third item is half as much as the second.

How much did each one cost?

First: $57.14
Second: $28.57
Third: $14.29

Posted in Brain Teasers

Cheese Made Backwards

What cheese is made backwards?

Edam cheese.

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What Looks Like Food

What looks like food, tastes like food, smells like food, sounds like food when you cook it, is grown in dirt like food, fills up your stomach like food, but is not food?

A poisonous mushroom. Since some types of mushrooms are edible, it can be very hard to distinguish between a safe mushroom and one that will kill you. Food is defined as a substance consumed to provide nutrition, therefore a poisonous mushroom that kills you doesn’t qualify as food, even though it shares all of the traits of a regular mushroom.

Other valid answers include anything that’s edible, resembles food, but is poisonous.

Posted in Riddles

Peggy’s Shy Parrot

Peggy wanted to buy a talking parrot and went down to the pet shop. She bought a parrot after being assured it would repeat any word or phrase it heard. Peggy bought the parrot and took it home, but it still hadn’t said a word after a few weeks. She returned to the shop to complain, but discovered the original assurances were still accurate. Why didn’t the parrot talk?

It was deaf so it couldn’t hear a phrase to repeat it.

Posted in Brain Teasers

Odd Word Out

One of these words does not belong, one of these words is not the same. What is it about the words that does not belong? It is more apparent than the first letter not being the same.

Selflessness
Selfishness
Strengthlessness
Defencelessness

Selfishness. The rest have only one of the vowels.

Posted in Brain Teasers

Same Three Digits with Sum of 800

When Florence and Willie finished playing darts, they proudly announced that their 3-digit scores added up to exactly 800 points. Furthermore, each of their scores shared the same 3 digits, without any repeating digits.

What were their two scores?

364 and 436.

You could figure this out mathematically, but instead, I plugged in digits that added up to 10 for the first column, 9 for the second column (since you carry the 1) and 7 for the third column (again, because you’re carrying the 1).

Posted in Brain Teasers

Working With Something In Its Eye

What always works with something in its eye?

A needle. Thread goes in the eye of the needle when you sew. If you sew…

Posted in Riddles

I’m Something You Might Eat But I Also Kill

I’m something you might eat, but I also kill.
I can cause blindness and burns.
Because of me, people lose limbs.
I’ve even been known to crash cars.

And yet I’m considered beautiful
Small children play with me and parents don’t mind.
Some people even live inside of me.

What am I?

Snow. Every kid has taken a bite of snow, but thousands of people die every year in snowstorms. Watch out for photokeratitis, otherwise known as snow blindness. And if you’re exposed to snow for too long, you can lose limbs to frostbite. Just an inch or two of snow makes them treacherous.

A recent snowfall makes the world white, and kids love to build snowmen, snow forts and have snowball fights. Some people live in igloos, built out of snow.

Posted in Riddles

Four Cards

Four cards are placed in front of you on the table, each with a number on one side and a color on the other. The visible cards show 3, 8, red and brown. Which cards should you turn over in order to test the truth of the statement that if a card shows an even number on one face, then its opposite face is red?

four-cards

You’d need to turn over only the 8 and brown card. Only a card with an even number on one face and which is not red on the other face can invalidate the stated rule. If you turn over the 3 card and it’s not red, it doesn’t invalidate the rule, nor does turning over the red card and finding it has the label 3.

This test was devised by Peter Cathcart Wason and is known as the Wason selection task. Less than 10% of test subjects got it correct in two separate studies.

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