Convert from mercantile pound to ounce [troy]

Unit Definition (mercantile pound)
The mercantile pound is a historic English unit of weight, the mercantile pound (libra mercatoria) was the commercial predecessor of the avoirdupois pound. Used from about 1100 to 1300, the mercantile pound contained 15 troy ounces or 7200 grains. This is equivalent to about 1.0286 avoirdupois pounds or 466.55 grams.

Unit Definition (ounce [troy])
The ounce [troy] is a second traditional unit of mass or weight. The troy ounce, traditionally used in pharmacy and jewelry, is 1/12 troy pound, 480 grains, or about 31.1035 grams. Thus the troy ounce equals 192/175 = 1.09714 avoirdupois ounces. This unit is the traditional measure for gold and other precious metals; in particular, the prices of gold and silver quoted in financial markets are the prices per troy ounce. The troy ounce is divided into 20 pennyweight or into 8 troy drams.