Questions tagged [calculation-puzzle]

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

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3answers
513 views

Simple Math Problem #3

Previous Puzzles(Not linked to this one): Simple Math Problem #1 and Simple Math Problem #2 Prove the equation: $-6439832+ = 9$ $-$ and $+$ are there just to tell that you can use only these two ...
8
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6answers
697 views

Pizzle - Will you ever show up, Rick?

NB: Pizzle = Puzzle + Riddle Chapter 1: Let's start (solved in comments) You can see me, but you can not catch me I'm lightweight, but I could lift you up easily Chapter 2: The First Piece (...
4
votes
5answers
435 views

Time-Motion puzzle

Time and Motion studies are well established. Here is an easy question: It takes 8 men 6 months to build 2 houses at a cost of $50,000. It takes 10 men 5 months to build 3 houses at a cost of ...
18
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5answers
3k views

All clock hands at equal degrees from each other

My dad once asked me: At what time will the second hand, minute hand, and hour hand on an analog clock all be $120^{\circ}$ from each other? It's a simple question, but I thought it was a fun ...
5
votes
1answer
464 views

Solve this puzzle. I created for my friend for FUN :)

My friend is very good at puzzles. so i thought of creating one by myself and try to see if he can solve. Finally I succeeded and he gave up. Interested people can try. Hint: use all four arithmetic ...
14
votes
2answers
19k views

What's the fewest weights you need to balance any weight from 1 to 40 pounds?

Suppose you want to create a set of weights so that any object with an integer weight from 1 to 40 pounds can be balanced on a two-sided scale by placing a certain combination of these weights onto ...
1
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1answer
240 views

What is the value of X?

24 6 63 132 4 14 23 x 17 The answer is either : 21, 14, 3 or 2
4
votes
1answer
304 views

M professors and N dishes

Suppose 'M' number of professors have to guess 'N' number of dishes on a roulette menu offered by a restaurant. This restaurant has a special "roulette menu" with N items, in which you choose a menu ...
2
votes
6answers
279 views

A Maximising Puzzle Gift for my Girlfriend and I's 28th month Anniversary

The 28th of december 2018 will exactly be the 28th month since I date my fabulous girlfriend, by this time she'll be 18 years old. Here's a puzzle I'll give her this day : Classical part Maximize $...
17
votes
2answers
3k views

N pirates steal their share of bananas to the benefit of a monkey

The following is a type of logic / math puzzle I've yet to see on this site. I feel it belongs because the kernel of this problem can be reworked into other puzzles. $N$ pirates find themselves ...
6
votes
8answers
548 views

Make $1,\dots,15$ using $3, 9, 9, 9$

This was inspired by many puzzles that use three/four numbers to create other numbers. I chose these numbers in particular because of this post. Can you find a way to make all the natural numbers ...
2
votes
1answer
171 views

What is the expected result? [duplicate]

I found the following puzzle through social media websites, What is the expected result? It seems to be easy. But, it needs concentration.
3
votes
2answers
755 views

make this sum using only +

A bit of a speed question this, first correct answer gets the check. Although you are allowed to use computers, it might be quicker not to. By placing only $+$ signs between some of the numbers on the ...
14
votes
6answers
3k views

Use 2 0 1 and 8 to make 67

Use $2$ $0$ $1 $ and $8$ to make the number $67$ RULES You must use all 4 digits. Only the digits 2, 0, 1, and 8 can be used. You can make multi-digit numbers out of the numbers. Examples: 20, 82, ...
4
votes
2answers
887 views

Use 2, 0, 1 and 8 to make 71

Use all and only the digits $2,0,1,8$ once each to make the number $71$. Allowed operations; anything not on this list is banned: $+,-,\times,\div, ()$ (parentheses and/or choose function) ...
2
votes
2answers
180 views

Use math symbols to produce 6 [duplicate]

How can we get (6) from these numbers? $2$ $2$ $2 = 6$ $3$ $3$ $3 = 6$ $4$ $4$ $4 = 6$ $5$ $5$ $5 = 6$ $6$ $6$ $6 = 6$ $7$ $7$ $7 = 6$ $8$ $8$ $8 = 6$ $9$ $9$ $9 = 6$ $12$ $12$...
15
votes
4answers
4k views

For how long did Lisa walk?

Lisa gets picked up from work by her husband at exactly 4 pm every day. One day Lisa finished work half an hour earlier and started walking to meet up with her husband. She met her husband on the way, ...
4
votes
5answers
2k views

What is her real age? [closed]

He : What is your age? She : 35 years old, ignoring the intervening Saturdays and Sundays. What is her real age?
6
votes
2answers
2k views

Number Series - 1,20,171

$1,20,171,?,9625,57756,288775$ Please find the missing number in the series. I have already tried with squares, cubes and progressions but couldn't find the problem.
4
votes
2answers
3k views

Find the missing number (triangle)

Find the missing number (triangle) Options: 9 8 7 10 Please write the logic also.
2
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3answers
87 views

Puzzle #1: Love In the Air

A couple that were just engaged decided to have their wedding in a hot air balloon. The biggest problem that the couple has is how many guests that they can invite. There are three different types of ...
3
votes
2answers
84 views

Puzzle #2: Prosecutor's Pathway

This one prosecutor has a very busy schedule. However, although his business can get busy, he is a lawyer faithful to his job, which is why he spends some weekend time at his private law firm. Since ...
1
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2answers
379 views

A Secret Math Society

I was about to try to join the famous Math club at my school when I stopped to hear my classmates doing the same. I didn't know that newcomers had to take a simple test to be qualified until my they ...
4
votes
1answer
182 views

Another pattern puzzle with a twist…well, not quite so

What are the next two terms of the following crazy sequence: I, h, 6, 9l, 52, 9E, 6h, __, __ ?
2
votes
2answers
791 views

Which switch is faulty?

How to solve this puzzle? This puzzle is taken from the book The Ultimate IQ Test Book by Philip Carter and Ken Russell.
4
votes
1answer
257 views

The wine paradoxon

You're a fellow salesman who happens to have to sell a barrel full of wine. The barrel has a capacity of 5 Litres. Unfortunately, your apprentice is a wine lover and steals some wine each night, ...
5
votes
1answer
314 views

How to choose the next board in the 8-puzzle?

I hope to have your help to solve the problem I am facing. I'm trying to make an 8-puzzle solver but I'm in doubt about how to select the next board, from the one they have already given me. Below I ...
0
votes
1answer
114 views

double the stone puzzle

Story: I've x number of stones. On my way, I will cross three wells. When I reach a well, then I will throw y number of stones ...
3
votes
1answer
542 views

I have more than one face, but I have no eyes. I roll out of hand during multiple tries

Riddle me this: I have more than one face, but I have no eyes. I roll out of hand during multiple tries. I very much often do not roll alone; I have a partner, who like myself, ...
5
votes
4answers
537 views

New Arithmetic Operator?

So my British friend proposed a new operator, but he wouldn't tell me how it works. He told me if I could figure it out then I could know. He's not very nice. Anyway, help me figure it out? 1 🎫 1 =...
8
votes
5answers
1k views

Streets Puzzle and Positions

The diagram below shows the street map of a city. If three police officers are to be positioned at street corners so that any point on any street can be seen by at least one officer, what are the ...
15
votes
9answers
5k views

Is this sequence that hard?

I published a sequence that seems difficult to the general public, so I've thought of posting it here. It has a very simple logic (language independent). Can you figure out the next number?
8
votes
3answers
566 views

Order matters twice

Mr. Accurado, a keen and sharp eyed professional thought of starting his special assignment at few seconds past midnight. However due to a distraction- which lasted for less than a minute - he could ...
2
votes
6answers
1k views

How cold is too cold? [closed]

On a day during a severe winter, somewhere in cold countries, I watched a weather report on a television. The report showed that on that particular day the temperature was 0° ....but due to some ...
8
votes
1answer
642 views

Magic Square Puzzle

Construct a 5x5 magic square. 1- Numbers from 1 to 21 can be used. 2- Sum should be 55 (Horizontally, Vertically and Diagonally) 3- Any 4 digits from 1 to 21 can be repeated only once. 4- The Numbers ...
28
votes
5answers
2k views

Making Things Difficult

An entry in Fortnightly Topic Challenge #35: Restricted Title 1. Factoring the Time Think fast! If you're looking for meaning, these clocks have some for you. Keyboards are Disgusting Gunky ...
1
vote
0answers
68 views

3 Horses out of 25 Horses [duplicate]

You've got 25 horses and you can host races in groups of 5. You don't have a stopwatch, obviously. Then what should be the minimum number of races that you should be conducting so as to ascertain the ...
9
votes
2answers
496 views

How old are Charlie's pets?

Last year at a picnic, Charlie told Julie's daughter the sum and the product of the ages of his dog and two cats, but she guessed the ages incorrectly. This year, he gave Steve's daughter the same ...
5
votes
1answer
330 views

Permutation At A Railway Track

Engines numbered 1, 2, ..., n are on the line at the left, and it is desired to rearrange(permute) the cars as they leave on the right-hand track. An engine that is on the spur track can be left there ...
4
votes
1answer
159 views

An Incorrect Summary of a Twenty-Two Day Tour

After a long but rewarding life in an office cubicle, Sally the office worker became Sally the retiree. Feeling unfulfilled, and with ancestors who had served admirably in the Navy, Sally the retiree ...
2
votes
1answer
150 views

Need little help

Note: Sorry, this puzzle almost similar with the last question: The main purpose of this QUESTION is: To know what types of this puzzle is exactly. It is still can be solve if I remove the most ...
11
votes
1answer
462 views

An Incomplete Puzzle

I'm sorry to offload some of my work as the puzzle creator on to you solvers. (No, I'm not.) At least there's only one clue missing, right? EDIT: When the puzzle is ready to be solved, there will be ...
1
vote
2answers
240 views

What are the chances on watching the clock? [closed]

This is a relatively straightforward little puzzle, but the answers are somewhat unintuitive or can prompt a new perspective. It might be an interesting little puzzle for a probability teaching ...
5
votes
3answers
1k views

A pokemon puzzle [closed]

You have recently caught N Pokemon and you also have M Pokemon candy bars. You can evolve any of your Pokemon by paying X candy bars. Alternatively, you can sell any of your Pokemon for a price of ...
-5
votes
1answer
102 views

Surprisingly(not literally) easy one? [closed]

What are the next two numbers in the following sequence: 0, 1, 4, 18, __, __. Please explain your logic.
2
votes
1answer
249 views

Extension to The grazing cows of Sir Isaac Newton

There is an earlier question, The grazing cows of Sir Isaac Newton, which says: Sir Isaac Newton's book "Arithmetica Universalis" contains the following famous puzzle: In $4$ weeks, $12$ ...
8
votes
3answers
2k views

Fully confused calculation

The sum of a three digit number (ABC) and another three digit number (DEF), where DEF is obtained by thoroughly shuffling* the original three digits of ABC, is 1000. Then, find all possible such pairs ...
12
votes
2answers
2k views

The grazing cows of Sir Isaac Newton

Sir Isaac Newton's book "Arithmetica Universalis" contains the following famous puzzle: In $4$ weeks, $12$ cows graze bare $3\frac13$ acres of pasture land, and in $9$ weeks, $21$ cows graze ...
3
votes
2answers
496 views

Your age and my age [closed]

This is not a very difficult problem, but it seems that it hasn't been asked here. It's one of my favorites, so here we go: I am twice as old as you were when I was as old as you are. When you ...
13
votes
16answers
10k views

A truly amazing way of making the number 2016

Find a mathematical expression that yields the value $2016$ while obeying the following rules: Each of the digits $1,2,3,4,5,6,7,8,9$ is used exactly once Decimal points are allowed You ...