projectEUREKA - a collection of problems, puzzles and trivia

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Showing 10 problems

Problem 280 - Probability of 6 numbers to be edges of a tetrahedron - Solution Not Verified

Choose six numbers at random, uniformly and independently, from the interval [0,1].
What is the probability that they are the lengths ...
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1 correct answer, 6 tries, 2 commented solutions , 1 solver: (maest) (Show all user statistics)

Submitted by Dan Dima (heartwork) on May 28 2009 | Discuss

Category probability

Problem 793 - binary tree - Solution Verified

If T is a binary search tree with the smaller elements in the left subtree, which of the following nodes contains the fourth smallest ...
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11 correct answers, 20 tries, 0 commented solutions , 9 solvers: (icradu) (joe.mike10) (bobbygriffin) (TimothyB) (guest) (harmanani) (xiaofan) (emer) (csilviu) (Show all user statistics)

Submitted by Joe (work) on December 17 2009 | Discuss

Category interview, Tags binary tree

Problem 1095 - What's wrong - Solution Verified

What's wrong with the following code.

#define FIFO1 "/tmp/namedpipe1"
#define FIFO2 "/tmp/namedpipe2"

int main() {
int ...
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7 correct answers, 22 tries, 1 commented solution , 4 solvers: (guest) (csilviu) (rekola) Amir Goharshady (Amirkg) (Show all user statistics)

Submitted by Joe (work) on July 26 2010 | Discuss

Category programming

Problem 117 - What are the numbers? - Solution Verified

In the calculation below, every letter represents a different digit from 1 to 9. What are they?
AB
xC
------
DE
+FG
------
...
Solve it!

9 correct answers, 12 tries, 0 commented solutions , 9 solvers: (alvaro) Doug Shasteen (dougs) Bogdan Mitu (bogdanm) (guest) (yat) (scterg) (Moonbeam) (Northwolves) (Amorydai) (Show all user statistics)
Source: FreePuzzles

Submitted by Lucian Badea (eklipsse) on April 14 2009 | Discuss

Tags math arithmetic puzzle logic brain teaser

Problem 397 - fly droppings on a meatball - Solution Verified

A meatball has four fly droppings on it. These droppings, are in random places and you must calculate the probability (x/y format, ...
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36 correct answers, 78 tries, 0 commented solutions , 8 solvers: (Icy001) (guest) Oscar Cunningham (Macbi) (Moonbeam) (Knobibrot) (stephisto) (mithsapprentice) (kamallohia) (Show all user statistics)
Source: tanya khovanova’s math blog

Submitted by Robert (uzurpatorul) on June 25 2009 | Discuss

Category probability, Tags math fun

Problem 433 - How many integers not divisible by 7 - Solution Verified

For how many positive integers x ≤ 10000 is 2^x - x² not divisible by 7?
Try to justify your answer without the use of computers. ...
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5 correct answers, 19 tries, 1 commented solution , 5 solvers: (bobbygriffin) (guest) (sherndon) (Moonbeam) (bengeance) (Show all user statistics)

Submitted by Robert Benea (robenea) on July 12 2009 | Discuss

Category math

Problem 969 - Relatively prime - Solution Not Verified

In how many ways can you fill a 3x3 table with the numbers 1 through 9 (each used once) such that all pairs of adjacent numbers (sharing ...
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2 correct answers, 4 tries, 0 commented solutions , 2 solvers: (godskalk) (csilviu) (Show all user statistics)

Submitted by (liz1980) on April 02 2010 | Discuss

Category math

Problem 20 - Dice game - Solution Verified

Two students play a game based on the total roll of two standard dice. Student A says that a 12 will be rolled first. Student B ...
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9 correct answers, 53 tries, 1 commented solution , 9 solvers: Robert (uzurpatorul) (swapspace) (alvaro) (Icy001) (Moonbeam) (yat) (csilviu) (kamallohia) (Amorydai) (Show all user statistics)

Submitted by Anca Vladeascu (vladeasca) on March 09 2009 | Discuss

Tags math puzzle probability

Problem 282 - Radius of a circle - Solution Verified

Lines l1 and l2 intersect in the plane as shown. Circles
A and B, each of radius 1 cm, are drawn tangent to l1
and l2 as shown. ...
Solve it!

6 correct answers, 12 tries, 0 commented solutions , 5 solvers: (yat) Nirmal Kirtisinghe (nirmalsuki) (guest) (flounders) (Moonbeam) (Show all user statistics)

Submitted by Robert (uzurpatorul) on May 30 2009 | Discuss

Category math, Tags geometry

Problem 549 - find A, B, C, D, E - Solution Verified

Find positive integers A, B, C, D, and E all less than 100 so that A² + B² + C² = D² + E² and A³ + B³ + C³ ...
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4 correct answers, 7 tries, 0 commented solutions , 4 solvers: (Moonbeam) (TimothyB) (Northwolves) (Amorydai) (Show all user statistics)

Submitted by Joe (work) on August 29 2009 | Discuss

Category general

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