Answer:
a) Since the woman starts from rest hence her initial velocity equals 0 m/s.
b) We can calculate the final velocity as follows
1) Distance covered while accelerating for 9 seconds is

2) Cruising speed =

Distance covered while travelling for 15 minutes at cruising speed =

Since the woman cover's 27 km in total hence the speed she travles with traffic speed can be calculated as

hence the final speed of woman =

Average velocity =

Her velocity 9 seconds into trip is calculated earlier as 22.5 m/s