If i lost challenge i lose Xp's too?

Answer 1

You can even get XP if you lose to challenger who has more XP in this language than you.
Explanations:
https://www.sololearn.com/Discuss/1091030/?ref=app
https://www.sololearn.com/Discuss/992991/?ref=app
https://www.sololearn.com/Discuss/940885/?ref=app
https://www.sololearn.com/faq/#q13
https://en.m.wikipedia.org/wiki/Elo_rating_system

Answer 2

Yes

Answer 3

hmm

Answer 4

isnt it obvious???