Which pairs of ratios could be used to form a proportion? a) 1/2 and 2/7 b) 1/2 and 2/2 c) 3/2 and 2/3 d) 5/1000 and 10/2000

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