ocr: Altogether you have 2+4+8+16 +32+.+a80 ancestors. This is 242-+2-+29+.-4290 people. Doy yousee that this a finite geometric series? It has 21 =2,r=2, a and n = 80. The sum of this series is Sso - - 1-r 01-a1r" 2-2-280 1-2 a 2.417 1024 2,41/,000,000,000,000,000,000,000,000,000. In 1 AD, the world population was about 250,000,000. In 1650, the world population - was about 550,000,000. In: 1990, the world population was about 0,600,000,000. ora about 5.5% of the 102,000,000,000 people who have lived since 1 AD. Doy yousee - - why you must have had some common ancestors since 1 AD? The Number of Y ...
