Convert from pennyweight [troy] to arratel, artel [Arab]

Unit Definition (pennyweight [troy])
The pennyweight is a unit of weight in the traditional troy system, equal to 24 grains or 1/20 troy ounce. One pennyweight is approximately 1.5552 gram.

Unit Definition (arratel, artel [Arab])
The arratel is a versions of a traditional Arab unit of weight; see rotl. The spelling "arratel" is used in Portugal as an alternate name for the libra.