Each coin flip is independent. Flipping one coin 10 times is the same as flipping 10 different coins at the same time and looking at all of the results. We know that a single coin will land on heads 50% of the time and tails on the other 50%. That's for 1 coin flip. Now, as we said before, each coin flip is independent of each other. That means, the second, third, fourth, etc. coin has the same chance as the first to be either heads or tails.

The 1st coin flip is 50%, the second is 50% and the tenth is also 50%. It's all the same as one single coin flip.