Combinatorics: Picking n marbles from 3 different groups of marbles.
8173
Number of ways to choose $n$ balls from $3n$ balls, distinguishable/indistinguishable.
147428
Probability of picking an odd number from the set of naturals?
136449
Combinatorics problem on $20$ people, $12$ months, and distinguishable groups
96086
Double Factorial: Number of possibilities to partition a set of $2n$ items into $n$ pairs
139913
In how many ways can $5$ balls of different colours be placed in $3$ boxes of different sizes if no box remains empty?
8458
Combinatorics problem based on Ferrers graph
110856
Number of ways to select $K$ people from $N$ people such that at least $r$ people are there in between them
87431
$n-$circular arrangement problem
150281
Am I on the right track to figure out this combinatorics problem?
139039
Stars and Bars Combinatorics Problem
99593
Determine the number of ways to colour a 1 by n grid using the colours red and white if an even number of squares are to be coloured red.
10272
A three-way duel (probability puzzle)
111954
Computing the cardinality of a combinatorial set
134440
An unexpected application of non-trivial combinatorics
54794
British Olympiad; Combinatorics Recursion
626
Sum of combinations with varying $n$
148776
A different approach in distributing $8$ distinct balls into $6$ distinct boxes