what comes after console.log to make output 60 in car speed question

Answer 1

What question?
https://www.sololearn.com/post/74857/?ref=app

Ok, I found it:
https://www.sololearn.com/learn/JavaScript/2975/
Read again the "tree" example. They are very similar. Click on "try it yourself" and play with the code if you want to get more confidence about what's going on.