On September 19, 2011 Aaron S from Florida posted this comment at The New York Times in which he claims that if you left one of the 400 wealthy people with just a billion dollars, he could not spend his fortune in 30 years at the rate of $100,000 a day. Is Aaron’s arithmetic right?

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