All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info
Home
Welcome to perplexus.info, flooble's perplexing puzzle portal. Here, we collect all sorts of puzzles, from simple logic questions and word tricks to in-depth math problems like probability and geometry. Click around and see if your brain is up to the task! If you're new here, make sure you sign up so that you can leave comments and submit your own problems!
> Logic> Probability> Shapes> General
> Numbers (2)> Games> Paradoxes> Riddles
> Just Math (1)> Science> Algorithms
Consider the integer powers of 7: a(n) = 7^n:
7, 49, 343, 2401, 16807,... 117649, ...

Prove that the second from right digit in all those numbers (excluding the 1st) is either 0 or 4.

(No Solution Yet, 1 Comments) Submitted on 2018-12-16 by Ady TZIDON   
On a train, Smithe, Robins, and John are the fireman, conductor, and the engineer, but NOT respectively. Also aboard the train are three businessmen who have the same names: a Mr. Smithe, a Mr. Robins, and a Mr. John.

Mr. Robins Lives in New York. The conductor lives exactly halfway between Columbus and New York. Mr. John earns exactly $20,000 per year. The conductor's nearest neighbor, one of the passengers, earns exactly three times as much as the conductor. Smithe beats the fireman in billiards. The passenger whose name is the same as the conductor's lives in Columbus.

Who is the Engineer?

(No Solution Yet, 46 Comments) Submitted on 2004-05-18 by Victor Zapana   
Difficulty: 4 of 5Concentric Circles and Equilateral Triangle (in Just Math)
Posted on 2018-12-15 by Danish Ahmed Khan (No Solution Yet, 2 Comments)
Difficulty: 4 of 5Colored triangle (in Sequences)
Posted on 2018-12-14 by Jer (No Solution Yet, 4 Comments)
Difficulty: 3 of 5Discs in Triangle (in Geometry) Rating: 3.00
Posted on 2018-12-13 by Danish Ahmed Khan (No Solution Yet, 2 Comments)
Difficulty: 2 of 5All digits distinct (in Numbers)
Posted on 2018-12-12 by Ady TZIDON (Solution Posted, 2 Comments)
Difficulty: 2 of 5A short list (in Numbers)
Posted on 2018-12-11 by Ady TZIDON (No Solution Yet, 1 Comments)
Difficulty: 4 of 5The 100th number (in Sequences) Rating: 5.00
Posted on 2018-12-10 by Math Man (No Solution Yet, 2 Comments)
Difficulty: 4 of 5Hoops (in Just Math)
Posted on 2018-12-09 by Danish Ahmed Khan (No Solution Yet, 2 Comments)
Difficulty: 4 of 5Maximal number of solutions (in Just Math)
Posted on 2018-12-08 by Ady TZIDON (Solution Posted, 5 Comments)
Difficulty: 3 of 5Rolling Ellipse (in Geometry)
Posted on 2018-12-07 by Danish Ahmed Khan (No Solution Yet, 1 Comments)
Difficulty: 3 of 58 distinct partitions (in Numbers)
Posted on 2018-12-06 by Ady TZIDON (No Solution Yet, 6 Comments)
Difficulty: 3 of 5Square after square creates a new square (in Numbers)
Posted on 2018-12-05 by Ady TZIDON (No Solution Yet, 3 Comments)
Difficulty: 3 of 5Logic or madness? (in Logic)
Posted on 2018-12-04 by Ady TZIDON (Solution Posted, 4 Comments)
Difficulty: 1 of 5A number plus its reversal (in Numbers)
Posted on 2018-12-03 by Ady TZIDON (Solution Posted, 6 Comments)
Difficulty: 3 of 5Heptagonal Beauty (in Geometry)
Posted on 2018-12-02 by Danish Ahmed Khan (No Solution Yet, 1 Comments)

Recently Posted Solutions:
Difficulty: 2 of 5All digits distinct (in Numbers)
Submitted By Ady TZIDON. Solution posted on 2018-12-15 08:47:56
Difficulty: 3 of 5Logic or madness? (in Logic)
Submitted By Ady TZIDON. Solution posted on 2018-12-13 06:00:56
Difficulty: 4 of 5Maximal number of solutions (in Just Math)
Submitted By Ady TZIDON. Solution posted on 2018-12-11 02:27:55
Difficulty: 1 of 5A number plus its reversal (in Numbers)
Submitted By Ady TZIDON. Solution posted on 2018-12-09 03:06:46
Difficulty: 2 of 5From sum to addends (in Just Math)
Submitted By Ady TZIDON. Solution posted on 2018-12-03 03:51:41
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (5)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2018 by Animus Pactum Consulting. All rights reserved. Privacy Information