How many diangonals are there in a hexagon?

Is there a simple formula for this? I think I am doing this the hard way.
Thank you!

Three diagonals per vertex. There are six vertexs. However, each diagonal has two ends (vertexes), so divide the number by two.

Using exactly 4-4's, make the equations using +,-,x, and divide to equal 0-9.

3 students will represent your school at a conference at the state capital. A drawing will be held to select the 3 representatives from a group of 5 finalsts. If you and your friend are both finalists, what are the chances that both of your names will be drawn?
Is it 2 out of 5 chance? Not sure how to figure this one.
Thank you

3 students will represent your school at a conference at the state capital. A drawing will be held to select the 3 representatives from a group of 5 finalsts. If you and your friend are both finalists, what are the chances that both of your names will be drawn?
Is it 2 out of 5 chance? Not sure how to figure this one.
Thank you