9 questions are relatively simple even if you do not remember exact formulas. Keep in mind though that you have to evaluate N!/K! of big numbers N and K. Use the fact that logarithm of product is the sum of logarithms. log(N!) = Sum_of (log(N)), so you need calculate it. You can code, you can use online calculators. They apparently expect you to use Python to do quickly the math. If you have a bachelor in STEM you will be fine. But those questions are not an issue if you plan ahead. What was the issue for me it was the last two problems. Specifically, the way how the test reads your output. Let me briefly explain. Go to hackerearth and practice some test coding. There are two options there - to test your code on a custom (your input) and the second option to submit the code. As for the first option, you set up your custom input, then run your code. It will ( at least it is supposed to) show EXPECTED OUTPUT and YOUR OUTPUT. If you did the thing right, they should match. As for the second option ("submit" button) the assessment will test your code against pre-planned input. Keep in mind though that you should not only provide the correct solution but also the fast one. Now, coming back to the code. The second coding problem was very simple but whenever I tried to test my code with the custom input the damn thing DID NOT SHOW EXPECTED OUTPUT! Instead it was showing an error for some inputs for which I was just sure I gave the right answer. The problem is that this thing is very sensitive to the output format, even extra space on the output means that your answer is incorrect. May be they will fix it. Or may be my browser failed me ( however I had no issue with the first problem). Of course I failed the test, the assessment did not accept my solution and I did not even know why. The coding question give you total 50 points (which is half of the total). May be I was just out of luck. Nonetheless I did not find the test difficult. I found it frustrating.