Answer 1

When I used to do challenges I faced this issue. The time wasn't enough to solve the problems in js or python. I figured out people just memorized stuff by checking the correct answers.
The reason I don't do challenges anymore :(

Answer 2

There are some harder challenges that you can't do in 30 seconds, but if you check the answer the next time you'll know the answer right away

Answer 3

Well, if you want to really know how to solve them quickly, it is to PRACTICE

Answer 4

Or u may solve the quizes in quiz factory.. there is no time limited there.. but beware quiz factory quizes r for users to review them so there may b some quizes that might give incorrect answers.. though I think 99.999% give accurate answer