Best Riddles of November 2012 | Best Riddles and Brain Teasers

#1 - Classic Logical Interview Puzzle

I have two rectangular wires.
Both of them have property that when i light the fire from one end , it will take 60 minutes to get completely burn.
However they do not burn at consistent speed (i.e it might be possible 1st 20% burn in 50 minutes and 80% can burn in 10 minutes).

So how could i measure 45 minutes ?

View Answer Discuss

Steps:
A) burn 1st wire from both end and 2nd wire from one end
B) After 30 minutes(when 1st wire gets completely burned out) , burn the second wire from 2nd end as well
C) when 2nd run completely gets burned , you know its 45 minutes.

#2 - Prison Break Riddle

Two prisoners 'Lincoln Burrows' and 'Michael Scofield' are locked in a cell.
There is open window approx 30 feet above the ground of the cell.
They are never able to reach there.

Then they plan to escape by a tunnel and they start digging out.
After digging for more than 20 days, Scofield comes with the different plan and they escaped.

what was the plan ?

View Answer Discuss

They use the dirt and bricks from the tunnel and stand on it then one on top of the other.

#3 - Shortest Meaningful English Sentence Puzzle

Find the smallest sentence with all the english alphabets.

View Answer Discuss

PACK MY BOX WITH FIVE DOZEN LIQUOR JUGS.

#4 - Most Famous Maths Puzzle

I can prove why 1 = 2

* Lets say y = x
* Multiply through by x xy = x2
* Subtract y2 from each side xy - y2 = x2 - y2
* Factor each side y(x-y) = (x+y)(x-y)
* Divide both sides by (x-y) y = x+y
* Divide both sides by y y/y = x/y + y/y
* And so... 1 = x/y + 1
* Since x=y, x/y = 1 1 = 1 + 1
* And so... 1 = 2

How is this possible ?

View Answer Discuss

Step 5 is invalid, because we are dividing by (x-y), and since x=y, we are thus dividing by 0. This is an invalid mathematical operation (division by 0), and so by not following basic mathematical rules

#5 - Tricky Password Teaser

There was some system error in a mailing website because of which passwords of some clients got changed.
Here is a conversation between a client and mailing-website executive person.

Client : My password is altered.
Client : I am not able to logged-in.
Executive : The password is distinct this time and it got eight letters , out of which two are same of your previous password.
Client: thanks , now i am able to logged-in.

Whats the client old and new passwords ?

View Answer Discuss

Old password : distinct , New Password : altered :p

#6 - Maths Classic Race Puzzle

Lavesh, Bolt, and Lewis race each other in a 100 meters race. All of them run at a constant speed throughout the race.

Lavesh beats Bolt by 20 meters.
Bolt beats Lewis by 20 meters.

How many meters does Lavesh beat Lewis by ?

View Answer Discuss

Lavesh beats Lewis by 36 meters.

It is tempting to guess that Lavesh beats Lewis by 40 meters, but when Lavesh finishes and is 20 meters ahead of Bolt, Bolt is NOT 20 meters ahead of Lewis (he's only 16 meters ahead), and it will take a couple more seconds before Bolt increases his lead over Lewis to 20 meters.

To figure out the answer, we let Lavesh's speed be A meter/second. So it takes him 100/A seconds to finish the race. At this point, we know that Bolt has run 80 meters (since Lavesh beats him by 20 meters). So Bolt runs 80 meters in 100/A seconds, meaning that he is running at a speed of (80/(100/A)) meters/second, or (8A/10) meters per second.

So we then know that it takes Bolt 100/(8A/10) seconds to finish the race, or 125/A seconds. At this point, we know that Lewis has run 80 meters (since Bolt beats him by 20 meters). So Lewis runs 80 meters in 125/A seconds, meaning that he is running at a speed of (80/(125/A)) meters/second, or 80A/125 meters per second.

Now that we know Lewis's speed, we just need to figure out how far he had run when Lavesh finished the race. Since Lavesh finished in 100/A seconds, we can determine that Lewis had run (100/A) * (80A/125) = 8000/125 = 64 meters when Lavesh finished the race. And so Lavesh beat him by (100 - 64) = 36 meters.

#7 - Marbles Puzzle

There is a box full of marbles,
all but two are blue,
all but two are green,
and all but two are red.

How many marbles are in the box ?

View Answer Discuss

There are 3 marbles (1 blue, 1 green, and 1 red).

#8 - Hard Number Series Problem

Can you find the next number in the below sequence
3 , 7 , 10 , 11 , 12 , 17 ?

View Answer Discuss

20(Twenty) : when you write them , these are only numbers having vowel 'E'

#9 - Find Number Puzzle

Can you find the least possible number such that

If the number is divided by 3 , it gives the remainder of 1;
If the number is divided by 4 , it gives the remainder of 2
If the number is divided by 5 , it gives the remainder of 3;
If the number is divided by 6 , it gives the remainder of 4.

View Answer Discuss

58.

Approach
LCM of the numbers 3,4,5 & 6 is 60.

So if i divide 60 by any of the four number , it gives remainder as 0.
Now to get reminder as desired, is should be 2 short of 60. (3-1,4-2,5-3,6-4 )

#10 - Maths Equation Puzzle

I know a way by which i can make i can get total of 120 by using five zeros 0,0,0,0,0 and any one mathematical operator.
Do you ?

View Answer Discuss

(0!+0!+0!+0!+0!)!
=(1+1+1+1+1)!
=(4)!
=5! is 5*4*3*2*1=120