Ustedes means you all. if it was one teacher I would use usted because it is the formal version of you, tu
Cual es tu nombre? = What is your name. The verb is cual
<u><em>Pedro es su primo </em></u>
<em>Hope that helps!! </em>
<em>have a wonderful day!! </em>
<em>if you ever need anything feel free to ask me!!</em>
