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

Five Three Two

What is the answer to the last equation?

5 3 2 = 151012
9 2 4 = 183662
8 6 3 = 482466
5 4 5 = 202504
7 2 5 = ?

10000 × (x × y) + 100 × (x × z) + transpose_digits(x × y + y × z)

transpose_digits() just swaps the digits

Posted in Brain Teasers

Cats and Kittens But No Mittens

Six men are carrying boxes holding six cats and each cat has 6 kittens. How many legs are there in total?

1020. There are 6 men with 2 legs each, for a total of 12 legs.
There are 36 cats with 4 legs each for a total of 144 legs.
There are 216 kittens with 4 legs each for a total of 864 legs
12 + 144 + 864 = 1020.

Posted in Brain Teasers

A Cowboy Rides Into Town On Friday

A cowboy rides into town on Friday, stays for three days and leaves on Friday. How did he do it?

The horse’s name is Friday

Posted in Riddles

The Train and the Tunnel

A train is a half mile long and is about to enter a 10 mile tunnel. If the train is traveling at 35mph, how long will it take for the entire train to make it through the tunnel, from the front of the train entering to the end of the train leaving the tunnel?

18 minutes.

Length of the train: 0.5 miles
Length of the tunnel: 10 miles
Total distance: 0.5 + 10 = 10.5 miles

Time = 10.5 miles / 35 mph = 0.3 hours = 18 minutes

Posted in Brain Teasers

Many and One

They are many and one,
They wave and they drum,
Used to cover a stare,
They go with you everywhere.

Your hands.

Posted in Riddles

No Head On Which A Hat To Place

I always run but never walk,
I sometimes sing but cannot talk,
No head on which a hat to place,
You always look me in the face.

What am I?

A clock. It runs all the time, it “sings” for hourly chimes, cuckoos or alarms, it doesn’t have a head (but does have hands) and you look a clock in the face to tell the time.

Posted in Riddles

13579U

What does this represent?

13579U

The odds are against you. All of the odd single-digit numbers are lined up next to the letter u, representing the word you.

Posted in Brain Teasers
Tagged with

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

I Never Even Touch the Ground

For some, I am used to get around.
I never even touch the ground.
Sometimes I fall and sometimes I float,
If I’m in the air, then take note.

What am I?

A boat. Boats are used to get around, they aren’t on the ground, but in the water. They rise and fall with the waves, and if they’re in the air, it may be due to rough seas and you should be careful.

Another possible answer is a blimp.

Posted in Riddles
Tagged with