Let D be the amount invested in desktop computers. Then the amount invested in the notebook computers is (50000-D). The total profit equation is 0.2*D + 0.25*(50000-D) = 0.23*50000. From the equation D == 20000. ANSWER. The amount invested at desktop computers is 20000 dollars. CHECK. 0.2*20000 + 0.25*(50000 - 20000) = 11500 = 0.23*50000. ! Correct !