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### Difficult Puzzles

Top 10 Difficult Puzzles

Difficult Puzzles 1 : Aeroplane Hardest Quiz
Difficulty ★★★★★     Popularity ★★★☆☆

The puzzle question is : On Bagshot Island, there is an airport. The airport is the homebase of an unlimited number of identical airplanes. Each airplane has a fuel capacity to allow it to fly exactly 1/2 way around the world, along a great circle. The planes have the ability to refuel in flight without loss of speed or spillage of fuel. Though the fuel is unlimited, the island is the only source of fuel.
What is the fewest number of aircraft necessary to get one plane all the way around the world assuming that all of the aircraft must return safely to the airport? How did you get to your answer?
Notes:
(a) Each airplane must depart and return to the same airport, and that is the only airport they can land and refuel on ground.
(c) The time and fuel consumption of refueling can be ignored. (so we can also assume that one airplane can refuel more than one airplanes in air at the same time.)
(d) The amount of fuel airplanes carrying can be zero as long as the other airplane is refueling these airplanes. What is the fewest number of airplanes and number of tanks of fuel needed to accomplish this work? (we only need airplane to go around the world)

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Difficult Puzzles 2 : Missing Piece Puzzle
Difficulty ★★★★☆     Popularity ★★★☆☆

Below the four parts have been reorganized. The four partitions are exactly the same in both arrangements. Why is there a hole?

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Difficult Puzzles 3 : Building Puzzle
Difficulty ★★★★☆     Popularity ★★★★☆

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

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Difficult Puzzles 4 : Wise Cipher Riddle
Difficulty ★★★★☆     Popularity ★★★☆☆

Decipher
yyyy u r, yyyyy u b, i c u r y+y 4 ? by sharks. How would you survive?

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Difficult Puzzles 5 : Challenging Mind puzzles
Difficulty ★★★★★     Popularity ★★★★☆

You are the ruler of a medieval empire and you are about to have a celebration tomorrow. The celebration is the most important party you have ever hosted. You've got 1000 bottles of wine you were planning to open for the celebration, but you find out that one of them is poisoned.

The poison exhibits no symptoms until death. Death occurs within ten to twenty hours after consuming even the minutest amount of poison.

You have over a thousand slaves at your disposal and just under 24 hours to determine which single bottle is poisoned.

You have a handful of prisoners about to be executed, and it would mar your celebration to have anyone else killed.

What is the smallest number of prisoners you must have to drink from the bottles to be absolutely sure to find the poisoned bottle within 24 hours?

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Difficult Puzzles 6 : Cipher Age Puzzle
Difficulty ★★★★★     Popularity ★★★★☆

If Susan is 10, Arabella is 20, and Jim and Neal are both 5, but Richard is 10, how much is Jennifer by the same system?

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Difficult Puzzles 7 : Hardest Math Riddle
Difficulty ★★★★★     Popularity ★★★★★

Create a number using only the digits 4,4,3,3,2,2,1 and 1. So i can only be eight digits. You have to make sure the ones are separated by one digit, the twos are separated by two digits the threes are separated with three digits and the fours are separated by four digits

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Difficult Puzzles 8 : Puzzle Boat
Difficulty ★★★★☆     Popularity ★★★★☆

At the local model boat club, four friends were talking about their boats.

There were a total of eight boats, two in each colour, red, green, blue and yellow. Each friend owned two boats. No friend had two boats of the same colour.

Alan didn't have a yellow boat. Brian didn't have a red boat, but did have a green one. One of the friends had a yellow boat and a blue boat and another friend had a green boat and a blue boat. Charles had a yellow boat. Darren had a blue boat, but didn't have a green one.

Can you work out which friend had which coloured boats?

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Difficult Puzzles 9 : Weighing Balance Puzzle
Difficulty ★★★★☆     Popularity ★★★★☆

You can place weights on both side of weighing balance and you need to measure all weights between 1 and 1000. For example if you have weights 1 and 3,now you can measure 1,3 and 4 like earlier case, and also you can measure 2,by placing 3 on one side and 1 on the side which contain the substance to be weighed. So question again is how many minimum weights and of what denominations you need to measure all weights from 1kg to 1000kg.

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Difficult Puzzles 10 : Pyramid Number Puzzle
Difficulty ★★★★☆     Popularity ★★★★★

The below is a number puzzle. It should be read left to right, top to bottom.
1
1 1
2 1
1 2 1 1
1 1 1 2 2 1
? ? ? ? ? ?
? ? ? ? ? ? ? ?
Question 1: What is the next two rows of numbers?

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Last Updated:2012-05-20

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3. great puzzles.........thank you for sharing!!!

4. awesome collection

1. Of what? Easy riddles?
Dude, gotta work out those riddles.

5. Easiest riddles ever...
Why?