how old was a person exaactly one year ago is exactly x years ago the person was y years old?

I do not understand the question.

To determine the person's age exactly one year ago, we can use the given information that "exactly x years ago, the person was y years old."

Let's break down the problem step by step:

- If exactly x years ago, the person was y years old, then their current age would be y + x.
- We want to determine their age exactly one year ago, so subtract 1 from their current age: y + x - 1.

Therefore, the correct answer is y + x - 1.