If 4 numbers from 1 to 1000 are chosen at random, one at a time, find the probability that they will be chosen in increasing order.

neurolover25
Feb 24, 2018

#1**+1 **

If we choose any four numbers from the first thousand integers, we will have

C(1000, 4) different sets of four numbers

And each can be arranged in 4! ways = 24 ways

But only one arrangement of each of these sets is in the desired order

So....the probability of the correct arrangement is just 1 / 24

CPhill
Feb 25, 2018