At Least One is a Boy

A couple has two children. At least one of them is a boy. Assuming the probability of having a boy or girl is 50%, what is the probability that both children are boys?

If you answered 1/2, you’re not without comrades, but the generally accepted answer by statisticians (though not without debate) is 1/3. This is because there are four possible combinations: boy-boy, boy-girl, girl-boy and girl-girl. Since we are told one of the children is a boy (but we don’t know if it’s the first or second child), we can rule out the girl-girl combination, leaving three remaining options. Only one out of 3 is boy-boy, so we get a 1/3 chance.

This is a well-known problem known as the Boy or Girl paradox. The other variation is this brain teaser.

Posted in Brain Teasers

Twice Is 99 More Than Half

What number satisfies this requirement? Twice the number is 99 more than half of the number.

66.

2 × 66 = 132 and 132 – 66 / 2 = 99.

Posted in Brain Teasers

1 2 3 4 5 6 7 8 9 = 100

This equation is incomplete: 1 2 3 4 5 6 7 8 9 = 100

One way to make it accurate is by adding seven plus and minus signs, like so.

1 + 2 + 3 – 4 + 5 + 6 + 78 + 9 = 100

How can you do it using only 3 plus or minus signs?

123 – 45 – 67 + 89 = 100

Posted in Brain Teasers

How to Escape?

A man is trapped in a room with only two possible exits. Through the first door is a room with an enormous magnifying glass causing the blazing hot sun to instantly burn anything that enters. Through the second door there is a fire-breathing dragon. How does the man escape?

Leave through the first door at night when the sun is down.

Posted in Brain Teasers

A Trail of Silver

If you carried my burden, you would be crushed.
Though not rich, I leave a trail of silver.

What am I?

A snail. They carry their homes on their back, and a house would crush a person (even the tiny houses). And the trail of silver is a bit of a stretch, but it’s the slimy, gooey substance snails leave behind them.

Posted in Riddles
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Only Useful When Full

I am only useful when I’m full,
Yet I am always full of holes.

What am I?

A sieve, used for straining food like pasta.

Posted in Riddles

Walks on Graves at Night

This walks on graves at night yet in homes during the day,
Men are scared of it, women like it, children play with it,
It lives on dates and salt,
It is covered in hair,
Its name starts with ‘M’ and it is mentioned in the Quran.

What is it?

Moths.
Most species of moths are nocturnal, yet they are attracted to light and can be found in homes. Men, in the most generic sense, can be scared of moths (see Mottephobia) as well as the damage they can cause as pests to bee hives, grain, flour, trees and agriculture. Women like moths because of the silk they produce. Children frequently chase and play with moths. Moths are attracted to salt and love to eat rotting fruit (such as dates). Some species of moths are densely covered with tiny hairs and of course it starts with the letter ‘m’. Lastly, moths are mentioned in the Quran (101:4 (Asad) [It will occur] on the Day when men will be like moths swarming in confusion)

Posted in Riddles

First In Flower and In Rose

My first is in FLOWER and in ROSE
My second is in FORK and well as HOSE
My third is in CROCUS but not in GNOME
My fourth is in RAKE never in HOME
My fifth is in HOE and also in WEEDS
My sixth is in SHEARS though not in SEEDS
My seventh is in LADYBIRD not in CREATURE

What am I?

Rockery

Posted in Riddles

What Everleigh Likes

Everleigh likes knights but not batteries, writing but not typing and to listen but not to sing. Does she like an unknown or a famous author?

Unknown. Everleigh likes words with silent letters.

Posted in Brain Teasers

Twist and Dance

I love to twist and dance.
Though wingless, I fly high in the sky.

What am I?

A kite.

Posted in Riddles