Jesse has 4 friends and 5 coworkers. Each day in the year 2021, Jesse talked to some number of friends: always at least one, but never all 4 in the same day. Each day in 2021, Jesse also talked to some number of coworkers, but never more than 3 coworkers in one day. Prove that there were two days in 2021 in which Jesse talked to the same set of friends and the same set of coworkers.

Jesse has 4 friends and 5 coworkers. Each day in the year 2021, Jesse talked to some number of friends: always at least one, but never all 4 in the same day. Each day in 2021, Jesse also talked to some number of coworkers, but never more than 3 coworkers in one day. Prove that there were two days in 2021 in which Jesse talked to the same set of friends and the same set of coworkers.

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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