The equation is 0.02*a + 0.10*(55000-a) = 0.052*55000. The solution is a == one click in Excel = 33000. Answer. $33000 to invest in fund A and the rest $55000 - $33000 = $22000 to invest in fund B. CHECK. 0.02*33000 + 0.10*22000 = 2860 dollars total interest = 0.052*55000. ! Correct !