Why some people have more xp in php for example

Question

I see that some people have 1000 XP on PHP or html and I only have 200, 300. why is this?

Answer 1

Because you entered more wrong answers in their questions ( since there is no challenge for php so this is only reason)

Answer 2

take part in challenges to up your XP

Answer 3

and they didnt spend xp on hints and solutions