If it takes 25 years for one generation to beget the next, what is the greatest possible number of male forebears living in 1100 A.D. from which a child born in 1950 could claim descent?
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Ok, so first off, we need to find the number of generations. Lets subtract 1100 from 1950 and divide the answer by 25 (answer gives us years, and we are dividing by 25 years to get the number of generations).
1950-1100 = 850
850/25 = 34 generations
So now we need to find how many ancestors this gives the child. So the typical person has 2 parents, 4 grand parents, 8 great grand parents, and so on. This means that the total ancestors to trace back to in 1100 is 2^34. You then, however, need to find only the number of ancestors in that "farthest back" generation. That should be 2^34-2^33, subtracting all the subsequent generations from the first one. That leaves us with 8589934592 ancestors.That number, however includes both male and female forbearers. In order to find the total number of male forbearers, we need to divide 8589934592 by 2. The total number of male forbearers that the child can trace back to is
4294967296 forbearing males in the year 1100.
If you are willing to respond, what class is this for?
1950-1100 = 850
850/25 = 34 generations
So now we need to find how many ancestors this gives the child. So the typical person has 2 parents, 4 grand parents, 8 great grand parents, and so on. This means that the total ancestors to trace back to in 1100 is 2^34. You then, however, need to find only the number of ancestors in that "farthest back" generation. That should be 2^34-2^33, subtracting all the subsequent generations from the first one. That leaves us with 8589934592 ancestors.That number, however includes both male and female forbearers. In order to find the total number of male forbearers, we need to divide 8589934592 by 2. The total number of male forbearers that the child can trace back to is
4294967296 forbearing males in the year 1100.
If you are willing to respond, what class is this for?
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you have 850 years Between the descendant and ancestors. so that's 24 generations back. if you count all parents back non inclusive that's 2 to the power of 23 or 8388608. this would be the maximum number of 22-great grandparents that person would have, dividing by 2 to get only males you get 4194304 22-great grandads. :D
hope this helped and thanks for the interesting Q
EDIT: damn did a genration as 35 years, sorry, look at the next answer it's more accurate
EDIT again: the answer ends up as 8 billion as the other answer states but the total world pop was only about 1 billion in 1100 AD, as there were more females than males that puts the maximum at about 450 million for males in 1100 AD assuming that he was a descendant of every male on the planet at that time.
hope this helped and thanks for the interesting Q
EDIT: damn did a genration as 35 years, sorry, look at the next answer it's more accurate
EDIT again: the answer ends up as 8 billion as the other answer states but the total world pop was only about 1 billion in 1100 AD, as there were more females than males that puts the maximum at about 450 million for males in 1100 AD assuming that he was a descendant of every male on the planet at that time.
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depends on how much children they have
if 1 child then (1950 - 1100) /25 = 34
if 2 children then (( 1950 -1100) /25) * 2 = 68
and so on
oh and divide by 2 if you only want males
if 1 child then (1950 - 1100) /25 = 34
if 2 children then (( 1950 -1100) /25) * 2 = 68
and so on
oh and divide by 2 if you only want males