perplexus.info :: logic puzzles, brainteasers, riddles and math tricks

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!

Categories (All Problem Categories)

> Logic	> Probability	> Shapes (1)	> General
> Numbers (1)	> Games	> Paradoxes	> Riddles
> Just Math (1)	> Science	> Algorithms

Latest: Eight Product Exercise (in Sequences)

A sequence {A(n)} for n = 1 to 8 is defined as:
A(1) = 2015, A(2) = 2/A(1), A(3) = 3/A(2), .....
A(7) = 7/A(6) and A(8) = 8/A(7)

Find A(1)*A(2)*....*A(8)

(No Solution Yet, 0 Comments)

Submitted on 2015-03-02 by K Sengupta

Bonus: No trigonometry, no algebra (in Geometry) Rating: 3.00

Look at the drawing below, where AB = BC = CD = DT = h, and TD perpendicular to AD:

                                   
                                   o T
                                   |
                                   | (h) 
                                   |
                                   |
  +----------+----------+----------o 
  A    (h)   B    (h)   C    (h)   D

The line AT makes an angle x with AD; the line BT makes an angle y with BD; the line CT makes an angle z with CD.

Using only geometry, prove that (angle x) + (angle y) = (angle z).

(Solution Posted, 10 Comments)

Submitted on 2005-12-23 by pcbouhid

Rational Rubric (in Just Math) Rating: 4.00
Posted on 2015-03-01 by K Sengupta (No Solution Yet, 2 Comments)

Equilateral fun (in Geometry)
Posted on 2015-02-28 by Danish Ahmed Khan (No Solution Yet, 2 Comments)

Back to the Bard (in Cryptography)
Posted on 2015-02-27 by Ady TZIDON (No Solution Yet, 2 Comments)

Prime and perfect (in Numbers)
Posted on 2015-02-27 by Danish Ahmed Khan (No Solution Yet, 3 Comments)

Cinq Celeb Commonality (in Riddles)
Posted on 2015-02-26 by K Sengupta (No Solution Yet, 1 Comments)

Academia, defeated, yesterday (in Word Problems)
Posted on 2015-02-26 by Ady TZIDON (No Solution Yet, 5 Comments)

Point Construction Ponder (in Shapes)
Posted on 2015-02-25 by K Sengupta (No Solution Yet, 5 Comments)

Next year vs the current year (in Numbers)
Posted on 2015-02-25 by Ady TZIDON (No Solution Yet, 5 Comments)

No other case (in Just Math)
Posted on 2015-02-24 by Ady TZIDON (No Solution Yet, 2 Comments)

Composite prime (in Numbers) Rating: 5.00
Posted on 2015-02-24 by Math Man (No Solution Yet, 2 Comments)

Bamboo Baffle (in Riddles)
Posted on 2015-02-23 by K Sengupta (No Solution Yet, 2 Comments)

Cryptajoke III (in Logic)
Posted on 2015-02-23 by Ady TZIDON (No Solution Yet, 2 Comments)

Integer Polynomial Illation (in Just Math)
Posted on 2015-02-22 by K Sengupta (No Solution Yet, 1 Comments)

Cubic Difference Conclusion (in Just Math) Rating: 4.00
Posted on 2015-02-21 by K Sengupta (No Solution Yet, 1 Comments)

Recently Posted Solutions:

Is it easy? (in Cryptography)
Submitted By Ady TZIDON. Solution posted on 2015-02-18 17:52:34

Deux Digit Determination (in Just Math)
Submitted By K Sengupta. Solution posted on 2015-01-20 06:59:00

Chinese New Year (in General)
Submitted By broll. Solution posted on 2015-01-19 03:21:41

Two squares in a circle (in Geometry)
Submitted By broll. Solution posted on 2015-01-14 05:57:02

So close, but no closer... (in Just Math)
Submitted By broll. Solution posted on 2015-01-14 05:52:28

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 (4)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:


perplexus dot info