I was going through this link - http://dictionary.cambridge.org/grammar/british-grammar/worth-or-worthwhile
However, I cannot find that the following sentence is wrong.
I wrote -
In conclusion, it all depends on the student whether taking a gap year is worth or not.
My teacher corrected -
In conclusion, it all depends on the student whether taking a gap year is worthwhile or not.
My question is why it is worthwhile and not worth. Here the gap year is like a noun. So, I am saying whether that noun is worth or not. For example - Do you think that buying a car (noun) is worth or not?