Convert from carat [international] to hundredweight [short, US]

Unit Definition (carat [international])
The carat [international] is a unit of mass used for diamonds and other precious stones. Originally spelled karat, the word comes from the Greek keration, a carob bean; carob beans were used as standards of weight and length in ancient Greece in much the same way barleycorns were used in old England. Traditionally the carat was equal to 4 grains. The definition of the grain differed from one country to another, but typically it was about 50 milligrams and thus the carat was about 200 milligrams.

Unit Definition (hundredweight [short, US])
The hundredweight is a traditional unit of weight equal to 1/20 ton. In the United States, where the currency was decimalized and there wasn't so much need to align the unit with the quintal and zentner, the hundredweight came to equal exactly 100 pounds (about 45.3592 kilograms). The U.S. hundredweight seems to have been invented by merchants around 1840. To distinguish the two hundredweight units, the British version is often called the long hundredweight and the American is called the short hundredweight or cental.