Charles invested $$2000$ in gold and a company working on prosthetics. Over the

course of the investment, the gold earned a $1\mathrm{.}8\%$ annual return and the prosthetics

earned $1\mathrm{.}2\%.$ If the total return after one year on the investment was $$31\mathrm{.}20,$ how much

was invested in each? Assume simple interest.