Please solve this problem

Which is equivalent to 10/12? options: 10/18 5/6 3/12 9/11

Select all of the following expressions that are equal to 2.5.

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