Mary walks west at 2.0m/s for 15 seconds, then north at 3.0m/s for 2o seconds and then east at 4.0m/s for 0 seconds. What is her displacement

Question

answer is (108m(N56 DEgrees E)

Answer 1

There is probably a typo:
...east at 4.0m/s for 0 seconds.
should probably read
...east at 4.0m/s for 30 seconds.

Sum up all the individual displacements to get the overall displacement.

Let +x=east, +y=north, then
(dx,dy)
=(-2*15+0+4*30, 0+3*20+0)
=(90, 60)
=108.17 in direction atan(90/60)=N56.3°E