An astronaut aboard a space ship in orbit around the earth is about 10,000 miles above the surface. a video from inside the ship shows the astronaut floating around weightless. this is because the gravitational force at that distance is negligible.

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