Your mind is a muscle. It is also a laboratory. Experiment -- find what works -- grow your cognitive ability.
Here are several questions to ponder:
1) If you receive a solicitation from a charity (you're the first one), and the email has a directive that you send the message out to two friends, and they are each to do the same, and so forth, how many generations of mailing will it take (yours is the first, your two friends are the second, and so on) for a single mailing to go out to more than 1 million recipients?
2) Applying the same circumstances and parameters as in question 1, above, what would your answer be if each recipient were required to send a copy of the email to three friends, instead of two.
3) If an executive consistently deposits 10% of her gross income into a special savings account, and her gross income grows at an average rate of 5% annually (her employer is a tightwad), how many years will it take before she accumulates (interest notwithstanding) one year's gross income (her first year's gross income) in the bank?
4) Why is it that when banks stop making loans to businesses, that the economy goes further into recession?
5) Why is it that when banks stop making loans to consumers (principally through credit cards, auto loans and home mortgages), that the economy goes further into recession?
I've given you quite a bit to think about. But then, I am confident that you're intelligent enough to reason these questions through.