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Results tagged with combinatorics
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user 18821
A puzzle based on combinatorics, which is the study of counting discrete structures. Use with [mathematics]
7
votes
Three Dice minimum value
Here is what I did:
I started with these 3 sequences which are able to reproduce the number 1-216. Basically this is the first three digits of a base 6 representation. Each row represents one die.
…
- 1,877
17
votes
Accepted
Four-by-four table with equal row and column products
Notice that each row and each column contains the numbers 1, 1, 2, 3, 4, 5, 6, 7
$$ \begin{array}{ a b c d }
4*7 & 1*6 & 3*1 & 2*5 & \\
3*5 & 2*1 & 4*6 & 1*7 &\\
1*1 & 4*5 & 2*7 & 3*6 &\\
2*6 …
- 1,877
11
votes
Accepted
Students in a class with the same name
Each of the numbers
0,1,2…,9,10 appears at least once.
In fact, the only way this works is if there are 1 students with name A, 2 students with name B, 3 students with name C, etc up to 11 stud …
- 1,877
5
votes
Bigger board with the least squares
Edit: I kept going back and forth between whether it should be 15 or 16 squares. I used color to convince myself that 15 does actually work.
1 is in the bottom left corner of a 8x8 square.
All of the …
- 1,877
5
votes
Blackboard problem with 2016
I tried tackling the problem numerically. I found that up to 13 layers of depth(the furthest I could go), there was no solution. First I inverted
$ f(x) = 2x+1 -> f^{-1}(x) = \frac{x-1}{2}$
$ g(x …
- 1,877