Refund amount = purchase amount * (g-g minus g)/g * return ratio. The reduction activity of Liu Fu Jewelry is a promotion and discount activity, and a part of the amount of gold bars purchased can be refunded when buying a specified weight of gold bars. The calculation formula is return amount = purchase amount * (g-g minus g)/g * return ratio. Luk Fook Group is one of the major jewelry retailers in Hongkong and China. It was established in 199 1.