4
votes
0answers
70 views

Adding Numbers Pattern

A few nights ago I couldn't sleep and so started doing this: I would take a number and add up all of its digits to get a new number and then add up all of those digits and so on until there was only ...
1
vote
1answer
49 views

Find A,B,C,D consecutive numbers based on written addition formula

$A, B, C, D$ are consecutive digits: $B$ is greater by $1$ than $A$, $C$ is greater by $1$ than $B$, $D$ is greater by one than $D$. Four $X$s are digits $A,B,C,D$ in unknown order. Find $A,B,C,D$ ...
2
votes
1answer
54 views

Alphametics Question

In the figure below, each distinct letter represents a unique digit such that the arithmetic sum holds. If the letter L represents 9, what is the digit represented by the letter T? ...
1
vote
5answers
164 views

Algebra problem stumping me

I have recently run into an algebra problem that goes as follows. Using the digits $1$ to $9$, $$ \left\{ \begin{align} A + B + C + D &= EF \\ E + F + G + H &= CJ \\ B + G + J ...
6
votes
2answers
319 views

Find the pattern puzzle

The question is: I thought of something like: 1st box: $(7-5)*(7+5)+50=74$ Yes! 2nd box: $(21-5)*(21+5)+50 =466$ Yes! 3rd box: $(21-7)*(21+7)+50=442$ No :( That's not an option. I have tried ...
1
vote
1answer
69 views

How to solve for getting average of them

I am trying to solve this problem If x+y= 6, y+z= 7 , and x+z= 9 , what is the average of x , y and z ? Well how i am trying to do is getting the value of 'X' , ...
1
vote
1answer
94 views

How I got this answer

Well i am new to this forum but old to stack exchange but i don't know much about mathmatics tags so sorry for the wrong tags if any. I have a question, but i want to know how i got its answer as 'D' ...
0
votes
1answer
117 views

A logical problem I can't solve. Please help. (About money) [closed]

I borrow 25 euro from 2 people that means I have 50 euro. I go to a restaurant, I eat and I pay 45 euro that means I have 5 euros remaining. I give 2 euro to each and that means I have 1 euro ...
7
votes
2answers
173 views

Come up with some fun “equation Limericks”

We were discussing "Limericks" in my Calculus class. Specifically, "equation Limericks". A Limerick is a poem with five lines. The first, second, and fifth lines should have nine syllables each and ...
1
vote
1answer
106 views

Two ball bounce problem

Two I had an interview, where they have asked me a physics puzzle. The question was, If two balls have been dropped at the same time from same height. suppose ...
10
votes
2answers
513 views

Star of David Math Puzzle

My son brought the following puzzle home from his 3rd grade math class. Are there any strategies for solving it besides brute force?
3
votes
0answers
140 views

Can this be only solved by trial and error?

The following question was asked in a competitive exam Rectangular tiles each of size 70 cm by 30 cm must be laid horizontally on a rectangular floor of size 110 cm by 130 cm, such that the ...
6
votes
1answer
353 views

How to find an expression whose value is 190

Given a set of numbers (in this case): 3, 7, 7, 100, 50 Either: prove it is impossible to form the number k = 190 using ( ) + - * / operators between sub set of the these numbers ex: 1000 = ((3 + ...
2
votes
3answers
475 views

Use three 11's and various math symbols to make an equation equal to 6

The puzzle is to use the following symbols $$+,\;-,\;*,\;/,\;(\;,\;),\;!, \;\sqrt(\cdot)$$ in order to make a valid equation out of $$11~~~~~~11~~~~~~~11 = 6.$$ (There are three elevens with space in ...
11
votes
1answer
592 views

Given a set of digits, what is the biggest number we can make using exponentiation - numberphile noodle quiz

The question is motivated by a question on a can of number noodles. Each item is a digit between $0$ and $9$. Clearly, if you form a string and consider it to represent a base $10$ integer, then ...
-3
votes
4answers
1k views

Clock Synchronization [closed]

There is a clock at the bottom of the hill and a clock at the top of the hill. The clock at the bottom of the hill works fine but the clock at the top doesn't. How will you synchronize the two clocks. ...
2
votes
2answers
187 views

Number of songs sung.

There were 750 people when the first song was sung. After each song, 50 people are leaving the hall. How many songs are sung to make them zero? The answer is 16, I am unable to understand it. I am ...
1
vote
1answer
445 views

How to solve multiplication alphametics?

I am referring to puzzles like these, where every letter represents a unique number (0-9): ...
1
vote
2answers
2k views

How to solve this alphametic (verbal arithmetic)?

I know I can get the answer for this puzzle but I'm struggling to see how to solve it. Every letter represents a different number (0-9): ...
0
votes
0answers
185 views

Puzzle: Representing age using digits from birth-year in order. Impossible cases?

I recently wrote my friend a birthday card and thought it would be fun to write her age using mathematical operations on the digits of her birth-year in order. For example she turned 36 and was born ...
3
votes
2answers
1k views

Puzzle : There are two lengths of rope …

You have two lengths of rope. If you set fire to the end of either of them, the rope will burn in exactly one hour. They are not the same length or width as each other. They also are not of uniform ...
1
vote
1answer
150 views

A rule to determine the crossed out digit

Lets take any integer, $z=abc\cdots$, form the sum of its digits, $a+b+c+\cdots$, subtract this from $z$, cross out any one digit from the result, and denote the sum of the remaining digits by $w$. ...
12
votes
1answer
335 views

Is the solution to this holiday puzzle unique?

I read the following question on this site: Start at 2011. By moving through the maze and doing any arithmetic operations you encounter, exit the maze with a result of 2012. You may pass through an ...
3
votes
0answers
100 views

Least characters in a numerical representation of integers

I was wondering what the shortest way to represent any given number is. For example, $387420489=9^9$. So, for this case, the smallest representation is of order 2 (2 numbers). Alternatively, ...
1
vote
1answer
53 views

Is it possible to determine the profit percentage? If yes, then how?

A shopkeeper who professes to sell his goods at cost price, uses a faulty balance that has one arm 4% longer than the other. Is it possible to determine his profit percentage? If yes, then how? ...
1
vote
2answers
257 views

Three numbers that multiply to ten (It gets harder)

I am working on a problem that involves the following: One must find three numbers, integers and/or decimals, that multiply to ten. Here's the catch: You must use all integers, $0-9$, in the ...
5
votes
2answers
227 views

What's the maximum possible score in this mathy solitaire puzzle?

Consider a deck of 52 cards in four mathy suits --two red: "adds" ($+$) and "subs" ($-$); and two black: "muls" ($\times$) and "divs" ($\div$)-- and thirteen numerical values --"A" (1), 2, 3, 4, 5, 6, ...
3
votes
2answers
1k views

Understanding Strategy:Minimum number of weighing to find the faulty bag

If Mr M buys $n$ bags of sands, each weighing a unit each except one bag. What is the minimum number of weighing is required to determine the faulty bag when: a two pan balance is used? ...
0
votes
1answer
247 views

A puzzle from Perfectly Reasonable Deviations from the Beaten Track by Richard Feynman

The following is a puzzle I found while reading Perfectly Reasonable Deviations from the Beaten Track by Richard P Feynman. There are 2 shops which sell oranges.At Shop A you get 2 oranges for 5 ...
1
vote
4answers
3k views

Absolute values of 1-10 in a pyramid form

_ _ _ _ \/ \/ \/ _ _ _ \/ \/ _ _ \/ _ you have numbers 1-10. you can only use each number once and the number below is equal to the absolute ...
5
votes
1answer
2k views

Riddle (simple arithmetic problem/illusion)

I'm not sure how well known this "riddle" is but here it goes. 3 people go to a restaurant, each buy food worth 10.00. When they're done, they give 30.00 to the waitress. She gives the money to the ...