## Saturday, January 30, 2016

### Fun with math!

I happen to love algebra so today I am going to give you a cute little equation.

2n = x

So what can you do with this?  You can figure out how many direct line ancestors you have in a given generation.  All you do is plug in the generation number for n.  x will be the total number of direct line ancestors.  You are generation 0, your parents are 1, grandparents 2, great-grandparents 3, etc.

For example, how many direct line ancestors are there in generation 6 (4th great-grandparents)?
26 = 64

How about generation 10 (8th great-grandparents)?
210=1024

How about generation 30 (28th great-grandparents)?
230 = 1,073,741,825 (that’s over a billion)

When you factor in normal/expected inbreeding you will have some overlap so these numbers will be a bit inflated.

For a bonus you can figure out how far back in time this is by giving each generation an average age. This is highly variable but let’s just say that everyone in your direct line had your direct line ancestor at age 25.

I was born in 1962 (don’t tell anyone).  30 generations will put me at the year 1212.  (30 generations x 25 years per generation subtracted from my starting year of 1962).

So how many generations is it for me to be at the time of Jesus?  Scholars put Jesus’ birth at around 4 BC.  That means I need 1966 years to get to Jesus.  That puts me at 78.64 or 79 generations.

If you have your family tree back this far I want to see the paper trail.