All Questions
Tagged with logical-deduction mathematics
645
questions
13
votes
1
answer
1k
views
Next date in the future such that all 8 digits of MM/DD/YYYY are all different and the product of MM, DD and YY is equal to YYYY
This problem is a little variation from this problem I made 2 months ago, which is inspired from this post.
When is the next date in the future such that all 8 digits of MM/DD/YYYY are all different ...
- 265
2
votes
1
answer
230
views
Find the value of '?' in 4x4 table of numbers [closed]
Solve for ?
50
15
10
60
45
31
5
87
40
22
42
?
9
4
3
14
- 29
2
votes
2
answers
197
views
Finding a mystery number - with three logicians
Three perfect logicians named A, B and C each select a positive integer and report their number to Mufti.
Mufti writes the sum of the three numbers on one card and the product of the three numbers on ...
- 73
18
votes
3
answers
1k
views
Finding a mystery number from a sum and product, with a twist
At a party of perfect logicians, Alzim and Era each select a positive integer and and report the number to Mufti.
Mufti writes the sum of the two numbers on a card and the product on another card. ...
- 643
1
vote
5
answers
558
views
Prove that all 101 balls have the same weight
In a collection of 101 balls, each ball weighs a whole number of pounds. If any one is removed from the collection, the remaining balls can be divided into two groups of 50 balls each with the total ...
- 3,193
3
votes
1
answer
182
views
Long Division when it is almost, but not entirely, wrong
Hmm, my last long division puzzle (Reconstruct a long division given less than a quarter of the digits, and all of those are wrong) didn't last the night. So let's try to make it harder. All of the ...
- 912
9
votes
1
answer
234
views
Reconstruct a long division given less than a quarter of the digits, and all of those are wrong
Inspired by "The Puffin Book of Brainteasers" I decided to try my hand at creating a long division missing digits problem where all of the displayed digits are wrong. On searching I found ...
- 912
1
vote
2
answers
214
views
Solve the Alphametic: SOUNDS / WOW = ELK
This is a long-division problem in which letters are substituted for numbers. Solve the problem. Determine the number value of each letter; and when the letters in each one have been arranged in order ...
- 21
-2
votes
2
answers
224
views
Flipping DIP switches
About 30 years ago, I bought a memory extension card. At first, I was hesitating: there were 8 dip switches and no manual. Then the owner recalled that 4 switches indicated the memory on the ...
- 429
1
vote
0
answers
189
views
Deadlock possible in Minefield?
A deadlock is a position in which neither player has won and neither player has a legal placement available. My question is, "Can you find a deadlock position in Minefield?" And, if you ...
- 335
6
votes
1
answer
517
views
Next future date such that the all 8 digits of date format DD/MM/YYYY is all different and the product of DD, MM and YYYY is a square number
This puzzle is inspired from here.
When is the future date such that the all 8 digits of date format DD/MM/YYYY is all different and the product of DD, MM and YYYY is a square number?
Note that "...
- 265
-4
votes
1
answer
150
views
Logic and Geometry Problem #6
Is it possible for a deadlock to occur in Necklace? Can there be a square on which neither Red nor Blue can place a stone?
If it is possible, I need to see an example of that.
If a deadlock is not ...
- 335
17
votes
2
answers
2k
views
Making a 2n-digit number divisible by 9
Alice and Bob play the following game, taking turns. Alice starts and writes a digit from the set M={1, 2, 3, 4, 5, 6} at the blackboard.
Bob appends another digit from the set M until a 2n-digit ...
- 12.2k
13
votes
7
answers
2k
views
Fewest number of prisoners needed
You are an assistant to the king, who has scheduled a party tomorrow. There are 1000 wine bottles in the king's possession, and unfortunately, 3 of them are poisonous. Consuming from any of these ...
- 101
3
votes
1
answer
381
views
Place numbers 1 through 9 in boxes (☐☐×☐=☐☐+☐☐=☐☐)
So recently I was scrolling through Youtube when I came across this video from MindYourDecisions that was about solving a legendary math puzzle.
The puzzle:
Place the numbers 1 through 9 in the ...
- 2,423