Yea it makes sense now. But how would i prove that the time taken would be 3.28 years?
Oh, good point! This is a little beyond what would be asked in the HSC, but it would look like this. First, you'd use the speed equation:
This allows you to link the length quantities in the equation above to the times given in the question. You get:
We substitute those quantities into the length contraction formula and that lets us solve for the velocity:
I skipped a few steps in that algebraic working, let me know if you need me to clarify it, but this should give you the direction! This working is subject to inaccuracy, I've never actually done this calculation before! However, the answer seems sensible to me, and note that this is pretty bloody quick
again, it is unlikely you'd be asked to specifically provide the calculation in the HSC, and I think the question was looking for something a little more general