Aragorn and Arwen Are NOT RELATED

[Nerwen]

Originally Posted by Galadriel55

If you tell me how any generations are between Elendil and Elros, I will be able to tell you how much maiar is in Aragorn, but I'll have to assume that either only one side of the family is descendants of Luthien, or both are - Since it's kinda hard to figure out when they married their kin and when they didn't. I've already done that for Elrond and Elros: they are 9/16 elf, 6/16 human, and 1/16 Maiar. To be specific, 5/16 Sindar, 3.5/16 Noldor, 0.5/16 Vaniar, 4/16 Beor, 1/16 Haleth, 1/16 Hador, and 1/16 Maiar. These calculations are exact. I love math, don't you?

1. There are twenty-two generations between Elendil and Elros (i.e not counting either of them).

2. Aragorn is definitely descended from Lúthien through both his parents.

Unfortunately, you can't get anything like an exact answer, because as you say we just don't know enough details.

Either you have to assume that neither Arathorn's nor Gilraen's family trees contained any previous intermarriages– which is downright impossible– or you ignore the number of generations altogether and assume the proportions remained more-or-less constant among Elros' direct descendants– which is highly unlikely, not to mention giving a rather surprising result. (Well, you wanted to do the maths yourself... be my guest.)