Seven of Fourteen
How many 7-element subsets of {1, 2, ..., 14} have a sum divisible by 7? Give an integer.
Related problems & prerequisites
Worth solving first
- Avoiding Multiples of Seven 6.0/10
- Hidden Progressions 5.0/10
- Ahead of the Two 4.0/10
Source: The case p = 7 of IMO 1995 Problem 6. Statement written for AxiomIQ.