Erin and mark are hiking down to the river. They descend 1,860 feet. They started hiking at 7:30 am and finished at 12:30 pm. What is the rate of change

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