olymmath

HMIC 2017 Problem 1

  • Answer

Kevin and Yang are playing a game. Yang has 2017+(20172)2017+\binom{2017}{2} cards with their front sides face down on the table. The cards are constructed as follows:

  • For each 1≤n≤20171 \leq n \leq 2017, there is a blue card with nn written on the back, and a fraction anbn\frac{a_{n}}{b_{n}} written on the front, where gcd⁡(an,bn)=1\operatorname{gcd}\left(a_{n}, b_{n}\right)=1 and an,bn>0a_{n}, b_{n}>0.
  • For each 1≤i<j≤20171 \leq i<j \leq 2017, there is a red card with (i,j)(i, j) written on the back, and a fraction ai+ajbi+bj\frac{a_{i}+a_{j}}{b_{i}+b_{j}} written on the front.

It is given no two cards have equal fractions. In a turn Kevin can pick any two cards and Yang tells Kevin which card has the larger fraction on the front. Show that, in fewer than 10000 turns, Kevin can determine which red card has the largest fraction out of all of the red cards.

Dataset text NuminaMath olympiads. Quoted with source.

Show the answer

2016+2015

Solutions

No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.

Add a solution

Similar problems

These problems have the most words in common with this statement.

Locator hmic/2017/p1 · Tag AQ8DAKJ614 · Edit this page on GitHub · Keys: j next, k previous