Answer:
Nicole's average speed is
.
Step-by-step explanation:
Given,
Speed of Kristen = 
Time taken by Kristen to cover the distance = 
Solution,
We can find out the distance traveled by Kristen by multiplying speed with time.


The distance traveled by Kristen is equal to distance traveled by Nicole.
As the question said Kristen left 2 hours later and cover the distance in 3 hours.
That means Nicole take 5 hours to cover the distance.
So, For Nicole;
Distance = 150 km
Time = 5 hrs
Here we use the formula of speed.

Now substituting the values, we get;

Hence Nicole's average speed is
.