# Difference between revisions of "Mock AIME 2 2006-2007 Problems/Problem 13"

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== Problem == | == Problem == | ||

− | In his spare time, Richard Rusczyk shuffles a standard deck of | + | In his spare time, Richard Rusczyk shuffles a standard deck of 52 playing cards. He then turns the cards up one by one from the top of the deck until the third ace appears. If the expected (average) number of cards Richard will turn up is <math>\displaystyle \frac{m}{n},</math> where <math>\displaystyle m</math> and <math>\displaystyle n</math> are relatively prime positive integers, find <math>\displaystyle m+n.</math> |

== Problem Source == | == Problem Source == | ||

4everwise enjoys playing and watching card games. In fact, he thought of this problem when watching Round 4 of the Professional Poker Tour. (Guy caught an Ace on the river.) | 4everwise enjoys playing and watching card games. In fact, he thought of this problem when watching Round 4 of the Professional Poker Tour. (Guy caught an Ace on the river.) |

## Revision as of 00:30, 25 July 2006

## Problem

In his spare time, Richard Rusczyk shuffles a standard deck of 52 playing cards. He then turns the cards up one by one from the top of the deck until the third ace appears. If the expected (average) number of cards Richard will turn up is where and are relatively prime positive integers, find

## Problem Source

4everwise enjoys playing and watching card games. In fact, he thought of this problem when watching Round 4 of the Professional Poker Tour. (Guy caught an Ace on the river.)