Is this relation a function?

The zoo collects $9.60 for every 24 tickets sold. how much will be collected for 400 tickets?

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

Edger needs 6 cookies and 2 brownies for every 4 plates how many cookies and brownies does he need for 10 plates