# Questions tagged [calculation-puzzle]

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

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### Finish The Pattern #1 [closed]

Given a pattern: 12, 22, 35, 68, 15, 28, 31, $n$ Find the next item at $n$. Pattern/sequence explanation required
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### Find the age of the ship and of the boiler

Some years back I was travelling by a cargo ship from New Zealand to Tahiti. I was curious to look around the ship one day and in the boiler room I asked a man how old the ship was. He smiled and ...
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### What is the maximum number of cities that can be destroyed?

As a commander of an army battalion, you have to plan the attack on some enemy cities which are connected by road-network. Before starting the attack, you have information about all the cities and ...
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### To be a bookworm

I have a complete set of encyclopaedias on my bookshelf, beautifully bound and neatly arranged with volume 1 on the left and volume 32 on the right. They were a talking point when I bought them 30-odd ...
562 views

### How many Pigeons are there?

There are pigeons sitting in a queue. The first one said, "There are 4 pigeons behind me." The last one said, "There are 4 pigeons in front of me." The middle one (or, one of middle ones) said, "There ...
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### Calculating row number and column number [closed]

What I am trying to do is calculate the row and column of which an id is in. For example I have the grid 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 As you ...
266 views

### What is my room?

You are heading to your hotel room but forget your room number. Try to check the key card but the digits are blurred You call to hotel desk info and a nerdy bell boy tell you: Your room have 4 ...
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### A Quote from what Movie?

Heads up: It's possible to solve this puzzle without writing computer code, but it is intended to be solved with computer help. This is a 2-stage puzzle. Stage 1: Calculation Puzzle Rules: 1. You ...
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### Vegas Street Magician Math Trick

I went walking with a friend of mine in Las Vegas last week. We turned a corner and saw a street magician doing some tricks for a crowd of 12-15 people. In most of his tricks, the magician would make ...
252 views

### How Much Bread For Her Budget? [closed]

A woman is looking through a store and sees a sign for 2 dollar bread saying "For every 10 loaves you buy, you get each for only 1.9 dollars!" A pretty strange deal, but she decides to take it. If ...
470 views

### Bitwise multiplication

Mr. EG has come up with a great coding scheme for (non-negative) integers in binary. To show off his creation, he demonstrates the following multiplications: ...
760 views

### Time teaser - clock losing time [closed]

I recall a question that went like this: If a clock is at noon on Sunday, and the clock loses 9 minutes per hour, what time will the clock next show the correct time? How do you work that one out?? ...
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### A number and its square

Find a four-digit number which is equal to the four least significant (rightmost) digits of its own square.
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### How many would die after E slightly pushes the structure in front of him? [closed]

As you can see in the picture, there are 5 people A, B, C, D, E. E is going to slightly push the circular structure so that the initial velocity of the structure on the inclined plane would be zero. ...
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### Building a 2 mile runway on a 1x1 mile island [closed]

You have a 1-mile long x 1-mile wide island. When taking off from a flat runway, a plane requires a runway of minimum length 2 ...
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### My grandfather's socks

My grandfather has a big drawer where he keeps his socks. The drawer contains more than 900 but less than 1000 individual socks. Each of his socks is black or blue, and there are more blue socks than ...
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### A self-referring number

Find a ten-digit number with the number of zeros in it as the most significant (leftmost) digit, the number of ones as the second most significant digit etc.
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### Arithmetic/Knowledge Step-By-Step Number Puzzle! (What Is The Final Answer?) [closed]

Start with the number of U.S. ounces in a U.S. gallon. Subtract the atomic number for Samarium. Add the amount of days in February on a leap year. Multiply this by 6 factorial. Divide this by pi ...
225 views

### Shooting an invisible rabbit [duplicate]

An invisible rabbit sits on one of the posts of an infinite fence. A local farmer cannot stand this fact and wants to shoot the rabbit down*. Every time the farmer shoots her gun, the rabbit jumps to ...
721 views

Start with an unlucky Friday number. Multiply by the gables on Hawthorne's house. Add the number that a stitch in time saves. Add the number of blind mice. Subtract the number of William Pene du Bois' ...
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### Computation without a computer

In the number $(1+\sqrt{3})^{2015}$, what is the 224th digit after the decimal point? You may NOT use a calculator, computer, or any electronic aid to answer this question. Only pen(cil), paper, and ...
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### 3x3 āMagic Squareā of Prime Numbers — Part II

Glad to know the previous puzzle, which was the first puzzle I posted in Puzzling, was warmly welcomed (Thank you!), and an optimal solution was found. Inspired by the comments there, here is the ...
2k views

### What is the next term in the sequence?

The first term is f(0), the last term is f(2000): 0,0,0,0,1,0,1,0,2,1,1,0,2,0,1,1,3,0,2,0,2,1,1,0,3,1,1,2,2,0,2,0,4,1,1,1,3,0,1,1,5,0,2,0,2,2,1,0,4,1,2,1,2,0,3,1,5,1,1,0,3,0,1,2,6,1,2,0,2,1,2,0,4,0,1,...
390 views

### What will be the price of the dog? [closed]

Two men had a certain number of camels, and sold those camels. The price of each camel was equal to the total number of camels they owned initially. They then bought a certain number of goats for that ...
297 views

### Scrap puzzle to count how many

There are 250 scraps. For each 11 removed, one extra can be obtained. How much maximum is possible, if one cut by one unit? I have read this somewhere, and one guy gave the answer as 25, but I can't ...
269 views

### There's an ARG I've been working on, and I'm stuck on this puzzle part II

Hees the first one incase you havent seen it. There's an ARG I've been working on, and I'm stuck on this puzzle So from that we got our password for this "problem" however we havent ...
895 views

### The Wizard's Gambit

An evil wizard has captured and thrown you into a dungeon. This is not a normal dungeon though. It's magical. Each room has an associated "level" and 9 doors. The first door can be used to go to ...
1k views

### Working schedule (with explanation) [closed]

Alice, Bob, Chris, Dave, Eric, Fred and Laura used to work in a restaurant 6 days a week, from Tuesday to Sunday (Monday is a day off). Every one works at least for one day, and at least two people ...
257 views

### Calculate RPM ratio A to D? [closed]

According to the picture: cogwheels A and D have 60 jags each, cogwheel B has 40 jags, and cogwheel C has 20 jags. If cogwheel B turns at 20 RPM, calculate the ratio of A's speed in RPM to D's.
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### In a certain language if the word STABILIZE is coded as JHXDJQSYA, then how is the word RESPONSES coded in that language?

In a certain language if the word STABILIZE is coded as JHXDJQSYA, then how is the word RESPONSES coded in that language? LRCRPOQDP PDQOPLRCR LRCRPPDQO LQCRPPDQO LRCRPPDOQ I tried it ...
839 views

### Dragon lizards in Hogwarts

Albus Dumbledore keeps 274 dragon lizards in his terrarium in Hogwarts. One day he removes two thirds of the male lizards from the terrarium; it is easy for him to tell the males apart from the ...
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### What, the answer isn't the No of the Yes is?

Doorknob knows exactly how to solve this, so I ask him to not answer this question. Well, here's the puzzle: No, an answer is the cube without A, No? The Yes is No. The squared answer, Yes, is to an ...
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### Sequence Brain Teaser: Fill the gaps to create arithmetic sequences

Fill in each blank unshaded cell in the diagram below with a positive integer less than 100, such that every consecutive group of unshaded cells within a row or column is an arithmetic sequence. This ...
634 views

### Paint the rectangle with least movement

There is a painting brush tool that can paint a circle area of $1$ unit radius. What is the shortest paint track for painting at least a $100*100$ units rectangle area on wall? How much did the brush ...
965 views

### The lights in the hotel

A hotel has $n$ rooms, numbered 1, 2, 3, etc. until $n$. At the hotel reception there are $n$ buttons, one for each room, also numbered 1, 2, 3, ..., $n$. Button 1 switches the light from on to off or ...
757 views

### Can the car or the bike travel further?

There is a car and a motor-bike. The car and the bike both have an spare tire. Now, the car has a total of 5 tyres (one spare tire included) and the bike has a total of 3 tires (one spare tire ...