You have two parents, four grandparents, eight great-grandparents, and so forth.
(a) if all your ancestors were distinct, what would be the total number of your ancestors for the past 42 generations (counting your parents' generation as number one)? (hint: use the formula for the sum of a geometric sequence.)
(b) assuming that each generation represents 25 years, how long (in years) is 42 generations? yr
(c) the total number of people who have ever lived is approximately 10 billion, which equals 1010 people. compare this fact with the answer to part
(a). what can you deduce? (select all that apply.)
1. there could not have been 42 generations in my line of ancestry.
2. people have been living on earth for less than 1,100 years.
3. some ancestors on different branches of the family tree must be the same.
4. some of my ancestors must not have had children.