Uber Data Scientist interview questions

I applied online ,after a week I got a call from the HR. I was scheduled two telephonic interviews. I was give a coding question on patients arriving to hospital as a Poisson distribution and doctor attending the patient as uniform distribution and write code to display the average wait time of the patient and total number of patients that are attended on a random day. The second interview was deep dive into Machine Learning, about PCA, equations on PCA, different features that could be given to a Uber driver to predict if the driver accepts the request or not. Multicollinearity, how to solve the problem. Time series forecasting techniques.