$5$ As part of a retirement strategy, a financial advisor placed $$40000$ for a client in equity funds earning $7\mathrm{.}25\%$ interest. The client also had money invested in stock certificates earning annual interest at a rate of $8\mathrm{.}5\%$ per annum. How much was invested in the stock rertificates if the total return on the investments over the period of a year was $$5025?$