Short answer is you must practice very hard on hackerrank for speed. They give 5 questions and 5th one is supposed to be hard. I found that my speed is 30 minutes per question and thus 1.5 hours is too short. By the time I finished 3rd it was already time over. I had written hackerrank test for another company and my average is 30 minutes. I am still not sure how to improve this speed. Btw, since I realized I won't be able to finish, I just skipped to last question to see how difficult it was. So I saw all 5 questions. Strangely I would rank last question as 2nd easiest.! It was 4th question that was most difficult. I am ranking based on the test scenarios to cover which is correct as per my experiences. I obviously didn't make it. But if you want to try then attempt only 3 questions. First two and then 5th one. If you can do more then better but I am not sure how someone can be faster. My thinking time was negligible. It was typing and reading code back that took all the time. Also, just for curiosity I checked hackerrank ranking of questions. I did find there ranking is not correct. I randomly took one difficult question to test and found it easiest one to date. It was easiest because only 5 lines were supposed to be modified. For me time is always proportional to the typing volume. Btw, I did try to shorten variable names to finish questions in time. Unfortunately it was too late. My advice: Give shorter variable and fn names so you save time. Attempt first 2 and then last. If time is left then attempt remaining one. As per their guidance they place most weightage on last so you should be through. Note that all the questions are solvable by anyone knowing little. It is speed that is the issue.