World line problem

[rbwang1225]

In the book of ED of Griffiths, p.506, prob. 12.22, I don't understand why the solution manual says that one can say she arrived at B before she left A?
Any help would be appreciated.

[jason12345]

In the book of ED of Griffiths, p.506, prob. 12.22, I don't understand why the solution manual says that one can say she arrived at B before she left A?
Any help would be appreciated.

The question asks:

Show, using a world line diagram, if it's possible for her to arrive before she set out if she can travel at a velocity greater than c.