Questions tagged [calculation-puzzle]

A puzzle that involves numerical calculations, such as multiplication and addition.

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7
votes
4answers
2k views

Multiplication Homework

$7*7~$ is $~25$ $6*6~$ is $~18$ $9*9~$ is $~41$ When is this true? Hint
5
votes
4answers
3k views

Replace all letters with a digit and solve the equations

There are ten expressions written in the scheme below from left to right and top to bottom. Replace all of the ten distinct letters in the scheme with a single digit between 0 and 9 and make the ...
2
votes
4answers
469 views

Boat traveling on a river [closed]

There's a boat traveling on a river. When it's going with the river flow, it takes 10 minutes to cover 1km, but when going against the flow, it takes it 15 minutes. How long does it take to cover 1km ...
2
votes
2answers
258 views

When did the tournament start?

[Inspired by the movie Bloodsport] The Kumite is an illegal underground fighting tournament organized in the typical single elimination bracket style. Think March Madness. All fights are fought one ...
6
votes
1answer
173 views

A man on a hill [closed]

A man walks up a hill at 2mph, and back down the same way at 4mph. Upon returning to where he started, what is his average speed?
20
votes
2answers
2k views

SPEND LESS MONEY alphametic

The well-known verbal arithmetic problem S E N D + M O R E ----------- M O N E Y explains (or at least it did the first time I knew about it) the story ...
0
votes
1answer
86 views

Average rain for 7 days [closed]

Assuming that Average rain rained for 7 days is 7 cm. First 6 days's average rain rained is 6 cm, then how much is rain rained on the 7th day of the week?
2
votes
6answers
2k views

Adding makes no sense [closed]

"Hey! If I were to add 6 to 13 I would get 7!", said Patrick slowly as he blew a stream of suspiciously maroon smoke out through his left nostril while calmly stabbing a funny-looking cigarette into ...
8
votes
1answer
815 views

A different extension of the sum and product puzzle

How far down the rabbit hole of not knowing can we go? While working on the generalization of I don't know the two numbers... but now I do, I thought of these two extensions. Both have the same ...
6
votes
1answer
2k views

Generalization of Sum and Product puzzle

I heard from a clever person that for the problem mentioned before: I don't know the two numbers... but now I do a solution exists even if we change 100 to infinity. So the formulation would be ...
44
votes
3answers
12k views

I don't know the two numbers… but now I do

Two perfect logicians, Summer and Proctor, are told that integers $x$ and $y$ have been chosen such that $1 < x < y$ and $x+y < 100$. Summer is given the value $x+y$ and Proctor is given the ...
-1
votes
1answer
107 views

maximum number of quarters using 10 dollars [closed]

A shopkeeper keeps 25% of the amount given as commission and returns the remaining back, for example if you give him 1$ he will return back 3 quarters. What is the maximum number of quarters you can ...
4
votes
2answers
379 views

Find the value of $m$

This question was asked in CSIR _NET 2014. I cannot figure out what are conditions given: Lunch-dinner pattern of a person for '$m$' days is given below. He has a choice of a vegeterian food and non-...
7
votes
1answer
436 views

Matrix sequence

While a one-dimensional sequence is represented by a list, a two-dimensional sequence (a sequence of sequences) can be represented by a matrix. Find the pattern behind the following sequence, where a ...
1
vote
3answers
392 views

Magic: the Gathering - Challenge #6.b: It's Gonna Cost You

Previous Challenge Next Challenge Background Alright I'm going to try a more clear approach to my last attempted puzzle. Given the mana costs given below, name cards with those exact mana costs ...
2
votes
1answer
3k views

How many watermelons left with Mr. Bean?

Mr. Bean leaves from place $A$ with 3 sacks that each contains 30 watermelons. He comes across 30 tolls till he reaches place $B$. At every toll, Mr. Bean has to give 1 watermelon as toll for each non-...
7
votes
5answers
8k views

Alternating numbers

Alternating numbers are numbers in which all digits alternate between even and odd. For example: 2703 and 7230 are alternating ...
4
votes
7answers
18k views

Water Jugs (10, 5 and 6) [duplicate]

I have three water jugs, one with 10 liters another with 5 and another with 6, how do i get 8 liters on the first one?
-1
votes
3answers
302 views

The birthday puzzles

Here is a couple of birthday puzzles based some time in the future: Puzzle 1 ...
0
votes
1answer
262 views

The Birthday Paradox [duplicate]

You run an office that employs 23 people. What is the probability that two of your employees have the same birthday? For the purposes of the problem, ignore February 29.
4
votes
2answers
412 views

Magic: the Gathering - Borrowed Time

Background Normal MtG rules apply here, except that whenever your deck is shuffled, you may assume it is stacked in any order you like. Puzzle Setup No permanents are currently tapped or have ...
-4
votes
2answers
240 views

The Billiards Problem

We have a billiards table with height $h$ and width $w$, as illustrated in the image below. Notice that it has no pockets. A ball with radius $r\ll w$ (can be regarded as a point) is propelled from ...
5
votes
5answers
1k views

Magic: the Gathering - Modern Engineering

The Challenge Using only lands and artifacts, your goal is to build a Modern-legal Magic: the Gathering deck that is capable of winning the game as quickly as possible, against an opponent who does ...
7
votes
4answers
977 views

Magic: the Gathering - Sealed Speed

BACKGROUND: Imagine you are playing a Magic the Gathering game of Sealed Oath of the Gatewatch. This means your deck consists of at least 40 cards, collected from four "Oath of the Gatewatch" ...
0
votes
3answers
10k views

A Water Jug Problem [duplicate]

Suppose you are given two jugs: a 4-gallon one and 3-gallon one, and neither has any markings on it. You have a pump that can be used to fill the jugs with water. What do you do so that exactly 2 ...
0
votes
4answers
1k views

Three Gallon Jug and 5 Gallon Jug [duplicate]

One of the classical puzzles is pouring water into the 5 gallon jug so there is 4 gallons of water remaining. This was popularized by Bruce Willis in "Die Hard with a Vengeance". I was wondering ...
3
votes
4answers
278 views

What is the number..? [closed]

This is a short number puzzle: Find a number $x$, which leaves remainder $1$ when divided by $2,3,4,5$ and $6$. Here is the some more explanation: $x$ divided by $2$ gives remainder $1$ $x$ ...
18
votes
1answer
1k views

Ernie and the Cake Cutting

Ernie had spent most of the afternoon at my place, helping me with the tile grouting in my new bathroom. It had been a difficult and messy job, so when he asked if I could do him a "small favour" I ...
4
votes
3answers
2k views

Find the missing number in this grid

Find the missing number in this grid. I am unable to find any pattern.
1
vote
3answers
400 views

Magic: the Gathering - Goblin Horde

The Challenge Using only lands and Goblins, your goal is to build a Magic: the Gathering deck that can win the game as quickly as possible, against an opponent who does nothing. You may assume that ...
0
votes
0answers
66 views

A very Puzzling Loss [duplicate]

This question was asked by teacher, a very simple one but still highly puzzling. Could you find the answer? There were three persons, A :- The Costumer, B :- The Cloth Shop Owner and C :- A boot ...
6
votes
2answers
607 views

A puzzle about flies and trains

So I have a website with some job interview type questions on it. Yesterday I pulled a question out the depths of my memory: A train enters a station at 50m/s where it starts to decelerate ...
15
votes
3answers
2k views

Trying to understand an unusual timestamp encountered on the web

I am writing an API to crawl a popular website, eksisozluk, kind of like Turkey's reddit, but more text based. On this website, you can get a list of the popular posts from the path /basliklar/...
2
votes
1answer
214 views

Magic: the Gathering - Impending Annihilation

Background Normal MtG rules apply here. Your solution must work regardless of any possible choices made by your opponents; assume they do whatever makes it most difficult for you to win. If you ...
5
votes
4answers
401 views

Magic: the Gathering - Challenge #6: Going Mental

Previous Challenge Background Today's puzzle is going to involve Mental Magic, a fun, memory-testing variant of magic. All of magic's usual rules apply, but with the following variations Any card ...
0
votes
2answers
334 views

Why does 11+1=3? [closed]

I don't get it. A friend asked ne this but I don't know what to say. I tried to see if it had to deal with integers or something, but I got nothing.
2
votes
1answer
204 views

Depressed Numbers [duplicate]

$12 = 0$ $1234 = 1$ $123456 = 2$ $12345678 = 4$ $369 = 2$ $248 = 3$ $2 = 0$ $3 = 0$ $5 = 0$ $7 = 0$ $11 = 0$ $13 = 0$ What does: $123456789 = ?$ Why? Hopefully isn't too hard, please ask if you ...
5
votes
5answers
873 views

Connect the numbers! (Sudoku-like challenge)

Rules You are given a square grid, with numbers (0-9) in some of its cells. You have to connect some of the numbers, so that each "island" of numbers has the same total sum. A number can have ...
1
vote
1answer
170 views

Find the numbers in sequence (Created by PC App) [closed]

Hi all. This image is a series of number in sequence created by computer app. You can see there are five numbers in above row and five numbers in row below. 1) Pls find what will be the numbers ...
5
votes
1answer
619 views

Mathematical alphabetical equation

Assume that the following three equations hold true: $C \circ I \circ D \circ A = B$ $O \circ K \circ M \circ G = C$ $Y \circ A \circ B \circ C = D$ Find the right hand side of the following ...
5
votes
2answers
819 views

“Magic: the Gathering” Challenge #3: Legends Rule

Previous Challenge Next Challenge BACKGROUND: Assume that this is a normal 20-life game of magic with no banned list (excepting cards from the 'Un' sets). If multiple solutions are tied for the ...
15
votes
1answer
883 views

“Magic: the Gathering” Challenge #2: Two Peas in a Pod

Previous Challenge Next Challenge BACKGROUND: Here's a puzzle for Magic: the Gathering players out there. I feel that this puzzle is in the scope of the site, and is no different than other puzzles, ...
7
votes
1answer
653 views

“Magic: the Gathering” Challenge #1: A Fiendish Puzzle

Next Challenge BACKGROUND: Here's a puzzle for Magic: the Gathering players out there. I feel that this puzzle is in the scope of the site, and is no different than other puzzles, e.g. chess, which ...
-2
votes
2answers
254 views

Colored stones on a chess board puzzle [closed]

We have a chess board of size n x n and there is exactly one stone on every square. We have green, blue and red stones. We must not have a row or a column full of stones of the same colour. We can ...
-6
votes
1answer
196 views

What will be the missing number? [closed]

What number comes next? 11,13,17,19,23,25,?
1
vote
2answers
743 views

Forty-Eight: What is the next bigger number?

How to solve this puzzle? Please explain with steps please!
0
votes
2answers
691 views

Walking and cycling [closed]

Claire walks to work at 6km/hr and Charles cycles along the same route. Normally Charles overtakes Claire outside the public library. One day Claire leaves 20 minutes late and Charles overtakes her ...
8
votes
2answers
687 views

Professor Halfbrain and the next square

Yesterday afternoon I met professor Halfbrain at a coffee place. The professor looked very tired. He told me that he hadn't slept for many days, spending his time with writing lots of zeros and with ...
1
vote
2answers
293 views

Time Traveller Maths

On a Wednesday afternoon, Marty McFly starts his DeLorean at 14:00 hours and travels 30 years in the past. After spending 3 days 30 minutes, travels 60 years to the future where he stays for another ...
3
votes
1answer
650 views

Clock values using only the digit 3

What is the minimal number of 3s required to create a clock where each of the hours is replaced by a mathemetical expression using only the digit 3 and standard mathematical operators? A friend ...