Questions tagged [logical-deduction]

A puzzle that requires formal logical deduction to arrive at the solution. This suggests more than merely reasoning through clues to find an answer (you might want [situation] for that).

2
votes
1answer
85 views

The NANNP Grid ( Not another Next Number Puzzle )

Simply figure out the last row...
0
votes
1answer
73 views

Place Your Bets 3 , last of the series

A harder sequence to figure out... What are the next 4 cards, including suits?
1
vote
1answer
51 views

Place Your Bets 2 - In sequence, of course

Your Cards... You have to figure out what the next row of 4 cards will be. There is a pattern in there somewhere, promise. Good Luck
2
votes
1answer
83 views

Place Your Bets - in sequence, of course

Your Puzzle There is some sort of pattern in cards below. Simply figure out what the next card should be. Note: You cannot re-use a card already in play.
3
votes
2answers
86 views

A Wine Problem for Puzzlers [duplicate]

Simple Follow the instructions on the label. In case you the image is too small, Given three bottles: 8, 5 and 3 liters capacity, divide 8 liters in half (4 + 4 liters) with the minimum number of ...
-4
votes
1answer
214 views

Write an equation using constants e, i, pi and phi [closed]

Without using numbers and using only permitted math operators, write an equation using the constants $e$, $i$, $\pi$ and $\phi$. Allowed operators..exponent...multiplication..subtraction...only. Use ...
-1
votes
1answer
84 views

The Puzzle of Puzzles - Pieces of Logic

The Story Johnny has added several new jigsaw puzzles to his somewhat large, and unusual collection this year. He likes Computer related puzzles, and the outdoors, as well. Your job, Determine each ...
2
votes
0answers
115 views

The Bad Clue Puzzle

The Jumbled Story Johnny might have had a couple beers when putting this one together. What he intended was a logic puzzle of friends, their favorite classic computer system, and how they used to ...
6
votes
2answers
202 views

Top Game Developers

Top Game Developers Back Story Okay fellow puzzlers, I hope you packed your lunch, this one is my most challenging puzzle to date... Johnny is writing an article about some of the top-selling ...
4
votes
2answers
140 views

Hidden Treasure Logic Puzzle

Ok, fellow puzzlers, here is my latest puzzle. They are getting progressively harder. Back Story While snooping around your grandpa’s attic, you came across a bunch of scribbled notes. They were in ...
5
votes
1answer
124 views

Video Game Auction - Logic Puzzle

Puzzle Difficulty: Very Challenging The Story Johnny loves his classic video games. He has collected most of them. Unfortunately, though, Johnny's Grandmother needs an expensive operation. He has to ...
3
votes
2answers
145 views

Looking for a Logical Puzzle with Scalability

I hope I am in the right place to be asking a question like this! That being said, I am experimentalist in need of a 'good' logical puzzle. There are aspects of the puzzle I would like and other ...
4
votes
6answers
2k views

Find 108 by using 3,4,6

Assemble a formula using the numbers $3$, $4$ and $6$ in any order to make 108. You may use the operations; $x + y$ $x - y$ $x \times y$ $x \div y$ $x!$ $\sqrt{x}$ $\sqrt[\leftroot{-2}\uproot{2}x]{...
1
vote
2answers
168 views

How many oranges did the litte girl originally have? [duplicate]

Please note: "She never had to cut an orange".
18
votes
9answers
1k views

One-one communication

5 people are standing in a circle - person A needs to tell his salary to person B, but none of the others should know A's salary. How is this possible, if every person only whispers to the person on ...
-2
votes
1answer
531 views

Don't be Greedy

this is a cs50 puzzle day 2019 question as you would know the questions have a one english word answer. will someone like to collab with me to solve all of them? there are 10 more of them.
1
vote
2answers
202 views

Sequence made of symbols

(My friend in real life gave me this)That's the original sequence: ⬅↕➡,⬅↕,➡,⬅,?,?,↕➡ I'm going to use other symbols to make it readable: (/), (/,), (/, ?, ?, /) I've noticed that the comma ...
12
votes
1answer
592 views

Reflections in a Square

An ideal billiards table (no friction, ideal reflections off of the walls, no pockets) is shaped like a square. From the bottom-left corner, shoot a point-sized cue ball at some angle. What is the ...
10
votes
1answer
588 views

Girl Hackers - Logic Puzzle

StackExchange Top Ranked Girl Hackers The Stack Exchange Hacking Federation (of course fictitious) has just released its list of top-ranked female hackers for the year. Using only the clues below, ...
12
votes
5answers
2k views

Sum letters are not two different

The following letters all have something in common which may not be obvious at a first glance: A B D H P No other letters share this attribute. Hint More ...
3
votes
5answers
355 views

A story about liars

Evelyn, Skylar, Alayna, Madelyn, Jonathon, Lara, Alyin, Felix, Iris, Bob and Roslina live on an island where some people always tell the truth, and the rest always lie. Roslina says "Alyin and Evelyn ...
18
votes
2answers
57k views

A man with two red pills and two white pills

Story: A Color blind man is travelling in a somewhat famous ship that had just a few people on board. Everything was smooth sailing for some days. One day,the man heard some noises from outside when ...
10
votes
2answers
1k views

8 Prisoners wearing hats

A warden lines up these prisoners. He announces, "I see a white hat." He then leaves the room. Every few minutes he comes back in and asks if anybody knows their hat color. Anyone who figured it out ...
20
votes
12answers
118k views

Four prisoners wearing black and white hats

There are four prisoners. All four prisoners will be freed, if at least one of them correctly guesses the color of the hat on his head. They can't speak to each other, and they can't touch each other....
27
votes
12answers
2k views

Shapes and letters. What is the missing box?

Finally, someone has figured it out. Good job.
9
votes
3answers
2k views

Science Themed Logic Problem

I have this question as extra credit for my chemistry class. Im passed the deadline for EC so i don't even care about that, the answer is just driving me crazy! No one else has figured it out that i ...
5
votes
3answers
316 views

Can't figure this one out.. What is the missing box?

I've been stuck on this for ages, and can't figure this out. What is the missing box, and the logic behind the answer? This was taken from a Korn Ferry Leadership Assessment practice trial.
15
votes
2answers
575 views

What is the Universal Translator censoring?

Lieutenant, launch the polar probes! Launching probes, sir. Failure, sir. Probes did not land at the poles. Well!? Where are they? Unknown, sir. Somewhere off-axis. They did land on ...
36
votes
5answers
10k views

Sabotage at Sea - Cursed Cruise liner?

(Warning: Heavy reading incoming. I suggest writing stuff down...) It's now the year 2150, and you're one of the few people who didn't leave earth twenty years ago. Why? A deadly disease overtook the ...
2
votes
1answer
162 views

Pattern Recognition: $7 \star 8$ =?

The following pattern was given to me by one of my friends: If $$\quad 5 \star 5 = 10$$ $$\quad 6 \star 6=18$$ $$\quad 7 \star 7=36$$ then $$\quad 7 \star 8 = ?$$ a) $54 \quad$ b) $51 \...
3
votes
12answers
2k views

English Logic Puzzle [closed]

On this site, I found this: "If some Smaugs are Thors and some Thors are Thrains, then some Smaugs are definitely Thrains." Options: TRUE, FALSE, NEITHER The answer given is FALSE. However, I ...
6
votes
1answer
411 views

Games and Puzzles

Four teams take part in a week-long tournament in which every team plays every other team twice, and each team plays one game per day. The diagram below on the left shows the final scoreboard, part of ...
11
votes
2answers
305 views

Bold, vivid family

I remember organising the colours of the rainbow in columns. In the way that I did, I could create the word RAINBOW from certain letters in each word, indicated by the columns they were each placed in....
6
votes
1answer
594 views

Bongard n°4: Neutral vs Town

This is my last puzzle before the holidays, have a nice summer everyone. Here's a link to the rules of these kind of problems: There are six boxes on the left, and another six on the right. The ...
6
votes
5answers
1k views

20 cards facing down

You have a row of $20$ cards facing down. A 'move' consists of the following actions performed in sequence: Pick a face-down card and flip it face-up If there is one, also flip the next card on ...
10
votes
4answers
1k views

JonMark Perry's Grid Logic Puzzle

Consider the following puzzle type proposed by JonMark Perry. Start with a square grid of arrows, each one pointing in one of the four cardinal directions. For example: You start at the ...
8
votes
4answers
1k views

A simple murder mystery puzzle that I came up with

A woman was found dead in her apartment. She was hanging from the ceiling but the detectives deduced that it was not suicide because of the bruises on her body (indicating a struggle) and the mess in ...
3
votes
1answer
1k views

Which of the six tiles is missing? — An IQ Test Question

Which of the six tiles below is missing? I honestly do not know the answer. I took a screenshot of this from an online IQ test a while back. If you know where it is from, please let me know, and I ...
4
votes
2answers
290 views

Gold, silver and bronze in the balance

Equivalent to finding three heaviest coins in order of weight, on a balance that holds one coin on each side. (Simplified, with some Wikipedia references corrected, from the original puzzle. The ...
4
votes
4answers
165 views

What is the minimum High Card Points needed for a partnership to be able to claim all 13 tricks in Bridge?

Assume you have basic knowledge of how a contract bridge game plays. There are 40 total HCPs in a set of cards. 4 for each Ace, 3 for each King, 2 for each Queen and 1 for each Jack. What is the ...
19
votes
1answer
961 views

Logic puzzle: Driving around the United States

For Super Bowl Sunday, here's a super-sized logic puzzle! This was a practice puzzle for a hunt I participated in a few years ago. There are ten delivery drivers driving around the United States of ...
0
votes
2answers
9k views

Which number should replace the question mark?

There is a picture. Find out what number is needed to replace this question mark.
5
votes
3answers
263 views

What's the hand of the lonely man?

Albert, Fred, Larry, Ron and Patrick are playing cards at Albert’s house with a regular 52 card deck that is missing all the 2s. Patrick has 10 cards, none of which are higher than 6. Ron has 13 cards,...
7
votes
1answer
188 views

Pattern Recognition problem : $… ,224,8,3,4,11,…$

The following pattern was given to me by one of my friend: $$\color{red}{224}$$ $$14 \quad \quad 8$$ $$4 \quad \quad \quad \quad \quad 3$$ $$8 \quad \quad \quad \quad \quad \quad \quad 4$$ $...
21
votes
8answers
7k views

Which one is the true statement? [closed]

All five statements below are true. None of the four statements below are true. Both of the statements above are true. Exactly one of the three statements above is true. None of the four statements ...
34
votes
3answers
5k views

Do better than chance

You and an opponent are playing the following game: Your opponent picks two different real numbers, however he wants to, and writes them on two cards, which he presents to you face down You choose ...
7
votes
3answers
388 views

Writing differences on a blackboard

The numbers 25 and 36 are written on a blackboard. At each turn, a player writes on the blackboard the (positive) difference between two numbers already on the blackboard, if this number does not ...
5
votes
5answers
653 views

The Pebbles Quiz

We are in a TV game. We have 8 same looking boxes, each of which has 2 pebbles. Each pebble could be either precious or not precious. We choose a box and the host, without looking inside the box, ...
1
vote
3answers
2k views

Matrix type IQ puzzle [closed]

Found these tasks, although not looking too advanced, I can't seem to solve them. What are the solutions and why? Task 1 Task 2
48
votes
15answers
6k views

Find the identity of the four troll brothers

The four troll brothers Wudhor, Xhaqan, Yijlob and Zrowag have the following properties: Wudhor always says the truth. Xhaqan always lies. Yijlob lies or says the truth unpredictably. ...