Convert from pfund [Denmark, Germany] to arroba [Spain]

Unit Definition (pfund [Denmark, Germany])
The pfund is a traditional German weight unit corresponding to the English pound. The pfund is equal to 16 unze or 32 lot. Traditionally the pfund varied in size from market to market, and the various German states adopted different standards, ranging from something close to the English pound (454 grams) to the Viennese pfund at about 1.2 pounds (560 grams). When Germany was unified in the late nineteenth century, the pfund was redefined as a metric unit equal to exactly 500 grams (about 1.102 31 pound).

Unit Definition (arroba [Spain])
The arroba [Spain] is a traditional unit of weight in Spain and Portugal, equal to 1/4 quintal. However, the Spanish and Portuguese quintals are of different sizes. In Spain, the arroba equals 25.36 pounds (11.50 kilograms); arrobas of very similar sizes were established in the Spanish speaking countries of Latin America. The arroba has also been used as a metric unit equal to exactly 15 kilograms. The name of the unit comes from ar rub', Arabic for "the quarter."