The Bornean orangutan is listed as Endangered and numbers approximately 41,000, while the Sumatran orangutan is considered Critically Endangered with an estimated population of 7,500. A century ago, more than 230,000 orangutans likely roamed in the wild.
Making the world better, one answer at a time. If you go to the United States Postal Service web-stie, you will find that one US First class stamp ($0.42) will cover the cost to mail a letter that weighs up to 1 ounce, about 28.35 grams. Thus, the average weight of a letter is one ounce or less. If you go to the United States Postal Service web-stie, you will find that one US First class stamp ($0.42) will cover the cost to mail a letter that weighs up to 1 ounce, about 28.35 grams.  Minor edit?
The stated weight is based on the number of sheets before they are cut, so a ream of 20-pound weight paper means 500 sheets weighs 20 pounds. Since each sheet equals four pieces of letter-size paper, your 20-pound baseline in this case is 500 sheets of four pieces each, for a total of 2000 pieces of letter-size paper.