Final answer:
The rate of arrivals at 9 am is 25.
Step-by-step explanation:
The rate of arrivals at 9 am can be found by evaluating the rate function, λ(t), at t = 1 (because 9 am corresponds to t = 1 in this scenario). Plugging in the value of t, we have λ(1) = 25(1)^2 = 25. Therefore, the rate of arrivals at 9 am is 25.