ranked arena placement matches and rp

hello, i have a question i ended my ranked arena placement matches and first: for win i get like 16 rp, for loss -12, but my driend gets like 80 for the win... why? also i was better than my friend in all of our matches( damage per game) but he stole a lot of kills.... he didnt finish his placements yet but i won 6/10 matches and in all i had the most damage, also i lost those 4 because i was playing against apex masters, diamonds,... and because my teammates were pretty bad.. ( i had 1260 dmg, but he had 125). is it normal that i got into bronze 3? its a kinda bad rank for 6 matches won and i was pretty good in all 10....

please answer me if u know why did this happen or if u know how does placement work 🙂

thanks