>All of them were on combinatorics/algorithms I have a PhD. I have had titles like "Principal Data Scientist","Senior Manager, Data Science" etc. Most of my

>All of them were on combinatorics/algorithms I have a PhD. I have had titles like "Principal Data Scientist","Senior Manager, Data Science" etc. Most of my colleagues think I am good at what I do. I would absolutely fail an interview where they ask these kinds of questions. I would need to revisit my probability and other textbooks for at least a few months to be able to pass these kind of questions. Being able to pass these types of interviews is a learned skill. I would recommend you look at it that way and disconnect it from "intelligence" or from the value you can bring as a data scientist. As far as the slow thinking, most jobs allow you to think slowly and work through things. You can make mistakes and fix them. There is no job where somebody says "We will release the hungry tigers on a plane full of children unless you solve a algorithm problem in 60 seconds." >In my country, there aren’t many DS internships, so if I fail a few more interviews, not sure if I can find new opportunities soon. I think this is the root of the issue. If there are only a few internships and lot of applicants, the employers can be as demanding or as harsh as they want. So it's really a reflection of the job situation, not you personally.