MathDB
TOT 181 1988 Spring S4 30 numbered cards, raise an arm game

Source:

May 20, 2020
combinatoricsgamegame strategy

Problem Statement

There is a set of cards with numbers from 11 to 3030 (which may be repeated) . Each student takes one such card. The teacher can perform the following operation: He reads a list of such numbers (possibly only one) and then asks the students to raise an arm if their number was in this list. How many times must he perform such an operation in order to determine the number on each student 's card? (Indicate the number of operations and prove that it is minimal . Note that there are not necessarily 30 students.)