projectEUREKA - a collection of problems, puzzles and trivia

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Displaying problems 1 - 10 of 1129 in total

Problem 335 - The Bear - Solution Verified

A vegetarian bear falls into a hole in the ground. The hole is 10 meters deep. After one second the bear reaches the bottom of the ...
Solve it!

176 correct answers, 1971 tries, 5 commented solutions , 10 solvers: (guest) Nirmal Kirtisinghe (nirmalsuki) (dimachka) (DuraCell) (octav) (Lazarus) Dan (6dd4) (maest) (skeptical scientist) (Moonbeam) (Show all user statistics)

Submitted by Robert (uzurpatorul) on June 12 2009 | Discuss

Category general, Tags puzzle physics

Problem 9 - Crossing the bridge - Solution Verified

Four men want to cross a bridge. The bridge is of a width such that a maximum of 2 people may cross at a time.

One man takes ...
Solve it!

208 correct answers, 814 tries, 1 commented solution , 10 solvers: Anca Vladeascu (vladeasca) Michael Smith (the_dude) Bogdan Stefan (bstefan) (anerey) Robert (uzurpatorul) Lucian Badea (eklipsse) Bogdan Mitu (bogdanm) (cesar) Vishwas Bhat (vishwasbhat) Andrei Radulescu (andreir2000) (Show all user statistics)

Submitted by Robert Benea (robenea) on March 01 2009 | Discuss

Category interview, Tags puzzle bridge interview

Problem 30 - 100! - Solution Verified

Consider the number 100!, wow many zeros are there at the end of 100!

Note: N!(N factorial) = 1 x 2 x ... (N-1) x N
Solve it!

122 correct answers, 566 tries, 4 commented solutions , 10 solvers: Dan Dima (heartwork) Robert (uzurpatorul) Robert Benea (robenea) Virgil (virgilm) Sebi (sebics) (alvaro) Lucian Badea (eklipsse) Bogdan Stefan (bstefan) Bogdan Mitu (bogdanm) Andrei Radulescu (andreir2000) (Show all user statistics)

Submitted by Michael Smith (the_dude) on March 17 2009 | Discuss

Category general, Tags puzzle brain teaser math factorial

Problem 837 - who is lying ? - Solution Verified

There are five guys named Alan, Bob, Casey, Dan, and Eric. Each one either always tells the truth or always lies. You overhear the ...
Solve it!

72 correct answers, 482 tries, 2 commented solutions , 10 solvers: (eijileona) (guest) (Northwolves) (bobbygriffin) (saeedghaemi) (Human445) Som Subhra Ghosh (somsubhra) Ken Puleo (shibbibidy) (godskalk) (yat) (Show all user statistics)

Submitted by Virgil (virgilm) on January 12 2010 | Discuss

Category logic

Problem 561 - Circles - Solution Verified

The following is a variant of a problem that appeared on a college entrance examination. In the figure below, the radius of circle ...
Solve it!

70 correct answers, 464 tries, 2 commented solutions , 10 solvers: (Knobibrot) (yat) (Moonbeam) (guest) (shpgxnor) (overbored) (sapo) (Reinier) (thisisbubs1) (davec727) (Show all user statistics)

Submitted by Michael Smith (the_dude) on August 31 2009 | Discuss

Category logic, Tags geometry

Problem 693 - How many legs - Solution Verified

There are 7 girls in a bus
Each girl has 7 backpacks
In each backpack, there are 7 big cats
For every big cat there are 7 little ...
Solve it!

71 correct answers, 404 tries, 2 commented solutions , 10 solvers: (Moonbeam) (bobbygriffin) (TimothyB) (guest) (yelly) Pradeep Kumbhashi (Deepzk) Michael (mikkl) (atif) (Rigas) Alex Velazquez (Alexmula) (Show all user statistics)

Submitted by Joe (work) on November 04 2009 | Discuss

Category math

Problem 681 - Rectangular grid - Solution Verified

A person is standing on a rectangular grid. He is allowed
to move one step south, north, east or west. After 4 moves he is supposed
to ...
Solve it!

43 correct answers, 363 tries, 1 commented solution , 10 solvers: (bobbygriffin) Robert (uzurpatorul) (Prof. Layton's Assisstant) (Moonbeam) (davec727) (bengeance) (Shrivali) (taylash24) (guest) (Fubsadoo) (Show all user statistics)

Submitted by (ilduderino) on October 30 2009 | Discuss

Category math

Problem 687 - Supercooled water in the freezer - Solution Verified

I put a bottle of water in the freezer every night before bed. In the morning, I take it out and drink it.

What are the possible ...
Solve it!

162 correct answers, 346 tries, 2 commented solutions , 10 solvers: (guest) (Moonbeam) (viva) (taylash24) (sk2) Virgil (virgilm) (yelly) (bobbygriffin) (pivo) (Astrogat) (Show all user statistics)

Submitted by (kokoshanel) on November 02 2009 | Discuss

Category trivia

Problem 576 - Faces - variant - Solution Verified

How many faces can you find?
Solve it!

16 correct answers, 335 tries, 0 commented solutions , 10 solvers: (guest) Joe (work) (davec727) (Moonbeam) Gaurav (justgiig8) Nirmal Kirtisinghe (nirmalsuki) Akshay Dixit (akshaydixi) (lucky99) (yat) (TimothyB) (Show all user statistics)

Submitted by Michael Smith (the_dude) on September 07 2009 | Discuss

Category trivia

Problem 97 - Crossing the desert - Solution Verified

An unlimited supply of gasoline is available at one edge of a desert 800 miles wide, but there is no source ...
Solve it!

60 correct answers, 319 tries, 1 commented solution , 10 solvers: Bogdan Mitu (bogdanm) Robert (uzurpatorul) (guest) (oreke1406) Jens Højlund (jens78) (yat) (overbored) (ghumphre) (brittybug_26342) (bcarpen6) (Show all user statistics)
Source: Martin Gardner

Submitted by Robert Benea (robenea) on April 09 2009 | Discuss

Category logic, Tags math

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