The formula for the third question which was the 2 marker question in P of F is
Vsquared / g tan bank angle
I hope that makes sense in this format. The answer you went for is the correct one....... with this formula.
The speed was 300kts in the question and to use this formula you have to work out the v speed (300kts) in metres per second squared, then divide by 10 tan 45 which would give the answer about 5m out.