Solo/Duo or 5v5 Flex

As some of you may know, Solo/Duo ranked came back today and I decided to play with a friend of mine. What happened was I was on a win streak, and ended up being placed in Silver, since last Season I was B1, 83 LP. Now I was wondering if when Season 7 starts, whether my Solo/Duo rank counts or the Flex Ranked counts. ;D