Mario’s Racing Grandma

Mario is testing out a new car at the racetrack. His grandmother took it for a mile lap and averaged 30mph. How fast does Mario have to drive in the second lap to average 60mph for the two miles?

90mph is an alluring answer, but it’s impossible. At 90mph the second lap would take 40 seconds. If Grannie’s first lap at 30mph took 2 minutes, traveling 2 miles in 2 minutes and 40 seconds is an average speed of 45mph. Traveling an average speed of 60mph for 2 miles would take 2 minutes and since the grandma’s lap took all of those 2 minutes, even if Mario could break the sound barrier he wouldn’t be able to average 60mph.

Posted in Brain Teasers

Fifty Quarters

You have fifty quarters on the table in front of you. You are blindfolded and cannot discern whether a coin is heads up or tails up by feeling it. You are told that x coins are heads up, where 0 < x < 50. You are asked to separate the coins into two piles in such a way that the number of heads up coins in both piles is the same at the end. You may flip any coin over as many times as you want.

How can you do it?

Take x coins, flip all of them and put them in one pile. The rest of the coins form the second pile.

Posted in 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?

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

Kings And Lords And Christians Raised Them

Kings and lords and christians raised them
Since they stand for higher powers
Yet few of them would stand, I’m certain,
If women ruled this world of ours.

A tower.

Posted in Riddles

Five Letters Sound Like Six When Pronounced

What five-letter word sounds like six letters when pronounced?

Cello. The pronunciation of c is ‘ch’, making it sound like the word has 6 letters.

Posted in Riddles

Bird Flying Over the Ocean

When a bird flies over the ocean a part of the body touches the water but doesn’t get wet. What part is it?

The shadow

Posted in Riddles

Ethan’s Grand Night Out

Ethan was going for a night out but his key fob battery had died and the button wouldn’t unlock his car door. How was he able to get in?

He used the key embedded in the key fob.

Posted in Brain Teasers

Pronounced As One Letter, Written With Three

Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I’m double, I’m single,
I’m black, blue, and gray,
I’m read from both ends,
And the same either way.

What am I?

Eye. It’s pronounced like the letter ‘i’, but written with three letters. There are only two letters used (‘e’ and ‘y’). The eye is double with two ‘e’s and represents a single eye. The eye is made up of various colors, some of which are black, blue and gray. And lastly, the eye is a palindrome, spelled the same forward and backward.

Posted in Riddles
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I Am, In Truth, A Yellow Fork

I am, in truth, a yellow fork
From tables in the sky
By inadvertent fingers dropped
The awful cutlery.
Of mansions never quite disclosed
And never quite concealed
The apparatus of the dark
To ignorance revealed.

— Emily Dickenson

Lightning.

Posted in Riddles

I Generate Fear But Am Quiet As A Mouse

I can generate fear and some say I come out of your ears. I’m quiet as a mouse but not welcomed in the house.

Smoke.

Posted in Riddles