Hi Tyrant,

1) After moving 2.7 km NE, the coordinates in x-y terms are (1.91, 1.91), i.e. 2.7 divided by the square root of 2. The person moved 1.91 km northwards and the same distance eastwards.

2) By moving then 7.4 km SE, the person moved 5.23 km southwards and 5.23 km eastwards (7.4 km divided by the square root of 2).

3) In the first run, the person moved 1.91 km northwards, in the second run it moved 5.23 km southwards, i.e. in the opposite direction.

4) Hence, the person's total shift southwards is 5.23 - 1.91 = 3.32 km. The shift in part (b) does not affect the southern position, taking place only in the east-west direction.

Please let me know if u r happy with my answer.

Cheers