Answer:
16 km/h
Explanation:
The relay stick would have the same velocity relative to Ingrid as the velocity she threw it because she threw it while running 9 km/h and the question asks for how fast it is moving RELATIVE to Ingrid, who also started off moving at 9 km/h.
Sorry if explanation is bad, this one was a bit of head scratcher for me to wrap my head around ig.