Fifty balls numbered 1 through 50 are mixed up in a barrel. how many balls must you draw from the barrel (without looking) to be sure that you have two even-numbered balls?

Suppose you are choosing a 6-digit personal access code. this code is made up of 4 digits chosen from 1 to 9, followed by 2 letters chosen from a to z. any of these digits or letters can be repeated. find the total number of personal access codes that can be formed. 492,804 341,172 39,917,124 4,435,236