How do you express a ratio as a unit rate?

Question

this is the first question 90.00 for 75 plates ... there are more and i am trying to help a friend, if you could just tell me what it means, i dont need the answer, i just need to know how to do it. thanks!

Answer 1

A unit rate has 1 on the bottom. Here you have 75 on the bottom (90.00/75) so divide both by the bottom number, 75, getting something over 1. The unit rate is (that number) per plate