Question

The next sentence is false.
The first sentence is true.

How is this possible?

Answer 1

because the next sentence is the second sentence that states its true, but the first sentence states its false. Therefore making the true sentence of false be true that it is false.

Answer 2

The next sentence is false.

This means that the second statement is not true.

If the second sentence says "The first sentence is true", it is wrong, which means that the first sentence should've been "the next sentence is true". Therefore, all sentences are false.

hope this helps