Riddles and Brain Teasers

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?

Show the answer »

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.

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

Posted in Brain Teasers

Singular When Adding an S

There are many English words that you can add an “s” to make it plural. But far fewer words become singular when you add an “s”. What are two examples of these much rarer words?

Show the answer »

Cares -> Caress
Princes -> Princess

Posted in Brain Teasers

AADFJJ

A A D F J J J M M N ?

What comes next in the series?

Show the answer »

O S. The series contains the first letter of each month in alphabetical order (April, August, December, February, January, July, June, March, May, November). O and S represent the remaining 2 months, October and September.

Posted in Brain Teasers

Tagged with sequence

I Can Create Peace

My first is in alphabet, my third is in Guinness, my sixth is in donut and my eighth is in elephant. My fifth doesn’t appear in walrus, my second isn’t in stealth, but my seventh is in tremendous and my fourth is in horse. I can create peace.

What am I?

Show the answer »

Everyone. Several words match the letter requirements, but only everyone satisfies the last statement. The other words are:

absentee
aperture
housetop
evermore

Posted in Riddles

Typing With A Busted Keyboard

My keyboard isn’t working correctly, with vowels not appearing and the space bar only working now and again. What did we mean by the sentence below?

SPCTH FNLFR NTRTH SRTHV YGSFT HSTRS HPNTR PRS!

Show the answer »

SPACE THE FINAL FRONTIER THESE ARE THE VOYAGES OF THE STARSHIP ENTERPRISE!

Posted in Brain Teasers

Guess the Three Words

Think of the six-letter name of a European capital city whose starting letter falls in the last half dozen letters of the alphabet and whose last letter is a vowel.

Now think of a three-letter words that means “permit”.

Last, combine all nine letters from the two words above. Rearrange the letters to form a word that you might call someone you like.

Show the answer »

1. Vienna
2. let
3. Valentine (Vienna + let)

Posted in Brain Teasers