Problem bank

Problem 178 of 333MediumProbabilityP178

Waiting for a smaller draw

  1. Draw U0∼Uniform(0,1)U_0 \sim \text{Uniform}(0,1). Then keep drawing independent U1,U2,⋯∼Uniform(0,1)U_1, U_2, \dots \sim \text{Uniform}(0,1) until one of them is smaller than U0U_0. Let NN be the number of extra draws this takes. Find P(N>n)P(N > n), P(N=1)P(N = 1), and E[N]E[N]. Is NN finite?