# Need help with math and statistics. [duplicate]

The world population is ~7 billion

Social Classes:

• Top .001% is ~70,000
• Second .01% is ~700,000
• Next .1% is ~7 million
• Rest 99.9% is ~6,993,000,000 (billion)

The odds of 1 person in the Rest grp meeting 1 person from the Top grp is it approx: 1 in 100,000 meets?

What are the odds of 1 person in the Rest grp meeting 2 people from the Top grp? is it: 1 in 100,000^2 or 1 in 10,000,000,000?

What are the odds of 1 person in the Rest grp meeting 2 people from the Top grp on the same year?

(Assuming in a lifetime of 100 years.)

• @amWhy yes I edited the original question instead of asking a new question by mistake. – nineyrold Apr 24 '14 at 19:34
• You can delete this post, then. – Namaste Apr 24 '14 at 19:35
• look here math.stackexchange.com/questions/158936/… :) – user145500 Apr 24 '14 at 19:38
• @Katy thanks for the link – nineyrold Apr 24 '14 at 19:39

First, $70,000/7,000,000,000$ $*$ $6,993,330,000/7,000,000,000$ does equal (approximately) $1$ in $100,000$. Second, both $1$ in $100,000^2$ and $1$ in $10,000,000,000$ are the same number, so it is both. As to the third question, one would need to know the number of times a particular person meets someone else in a year; I would estimate this at a hundred thousand times per year, which means that a normal person would have a $1$ in $100,000$ chance of meeting two people in the top social class in any particular year. Of course, all of this is assuming that no factors other than pure chance are involved; in many countries there are caste systems that separate the upper and lower classes.