MathDB
Nepal National Olympiad

Source: Nepal Mathematics Olympiad

April 22, 2018
combinatorics

Problem Statement

Problem Section #4
c) A special deck of cards contains 4949 cards, each labeled with a number from 11 to 77 and colored with one of seven colors. Each number-color combination appears on exactly one card. John will select a set of eight cards from the deck at random. Given that he gets at least one card of each color and at least one card with each number, the probability that John can discard one of his cards and still have at least one card of each color and at least one card with each number is pq\frac{p}{q}, where pp and qq are relatively prime positive integers. Find p+qp+q.