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 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!
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Latest: Set Theory (in General)

The following is a list of 15 thought provoking statements
about sets where a true or false answer is needed.
A denotes any set, F the set {1,2}, φ the empty set,
and ℘(S) the set of all subsets of set S (i.e, the power
set of S).

a)   φ∩{φ} = {φ}
b)   φ∪{φ} = {φ,{φ}}
c)   φ ∈ ℘({φ,{φ}})
d)   {φ} ⊆ A
e)   φ ⊆ A
f)   φ ⊆ ℘(A)
g)   {{φ}} ⊆ ℘(φ)
h)   {φ}∩φ = φ
i)   ℘(φ) = {φ,{φ}}
j)   φ ∈ A
k)   φ ∈ ℘(A)
l)   {φ} ∈ ℘(A)
m)   {φ}∪φ = {φ}
n)   φ ⊆ ℘(F)-φ
o)   {φ} ⊆ {{φ,{φ},{{φ}}}}

From "Bridge to Abstract Mathematics",1987
by Ronald P. Morash.

 (No Solution Yet, 3 Comments) Submitted on 2014-04-19 by Bractals
Bonus: The Tunnel (in Logic) Rating: 3.54
You have entered a mysterious tunnel with your friend. As you get to the middle of the room, flames rise at both ends, disallowing you from exiting.

On a table you see a row of 7 bottles of potions, each a different size. The largest bottle is second from the left, and the smallest is fourth from the right. There also is a riddle.

"Danger lies before you, while safety lies behind,
Two of us will help you, whichever you would find.
One among us seven will let you move ahead,
another will transport the drinker back instead,
Two among our number hold only nettle wine,
Three of us are killers, waiting hidden in line.
Choose, unless you wish to stay here forevermore,
To help you in your choice, we give you these clues four
First, however slyly the poison tries to hide
You will always find some on nettle wine's left side;
Second, different are those who stand at either end.
But if you would move onward, neither is your friend;
Third as you see clearly, all are different size.
Neither dwarf nor giant holds death in their insides;
Fourth, the second left and the second on the right
Are twins once you taste them, though different at first sight.

Which bottle will contain the potion to allow you to continue on in the tunnel, and which one will allow your friend to go backward in the tunnel?

(Taken from "Harry Potter and the Sorcerer's Stone")
 (Solution Posted, 16 Comments) Submitted on 2003-12-16 by Gamer
Mean Muse (in Just Math)
Posted on 2014-04-18 by K Sengupta (No Solution Yet, 0 Comments)
Neighbors (in Numbers)
Posted on 2014-04-18 by Ady TZIDON (No Solution Yet, 8 Comments)
No way to win (in General)
Posted on 2014-04-17 by Ady TZIDON (No Solution Yet, 4 Comments)
Murderer Detection (in Riddles) Rating: 3.00
Posted on 2014-04-17 by K Sengupta (No Solution Yet, 2 Comments)
Cubic Sequence? (in Sequences)
Posted on 2014-04-16 by K Sengupta (No Solution Yet, 2 Comments)
Colorful hats (in Logic) Rating: 2.00
Posted on 2014-04-16 by Math Man (No Solution Yet, 4 Comments)
Mod 3 alphametics (in Just Math)
Posted on 2014-04-15 by Ady TZIDON (No Solution Yet, 2 Comments)
My phone is 2543663 (in Probability) Rating: 4.00
Posted on 2014-04-15 by Ady TZIDON (No Solution Yet, 5 Comments)
Pseudo-FIBO (in Sequences)
Posted on 2014-04-14 by Ady TZIDON (No Solution Yet, 5 Comments)
Question Quandary (in Logic) Rating: 3.00
Posted on 2014-04-14 by K Sengupta (No Solution Yet, 2 Comments)
The right subset (in Word Problems)
Posted on 2014-04-13 by Ady TZIDON (No Solution Yet, 1 Comments)
Geometric Sequence Settlement II (in Just Math) Rating: 3.00
Posted on 2014-04-12 by K Sengupta (No Solution Yet, 1 Comments)
Upside down (OEIS A045573) (in Numbers)
Posted on 2014-04-11 by Ady TZIDON (No Solution Yet, 6 Comments)
Synonym Set (in Word Problems)
Posted on 2014-04-11 by K Sengupta (No Solution Yet, 1 Comments)

Recently Posted Solutions:
Q: What is this sum? (in Numbers)
Submitted By Ady TZIDON. Solution posted on 2014-04-09 00:05:29
It is not that easy (in General)
Submitted By Ady TZIDON. Solution posted on 2014-04-08 23:53:41
Logical connectives (in Algorithms)
Submitted By Math Man. Solution posted on 2014-04-03 18:51:23
2 to 1 Bisector (in Geometry)
Submitted By Bractals. Solution posted on 2014-04-03 16:39:37
Liars Logic (in Liars and Knights)
Submitted By tomarken. Solution posted on 2014-03-24 13:44:53

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