Let x= amount invested at 4%. Then the total interest equation is 0.05*(2x) + 0.04*x = 364 0.1x + 0.04x = 364 0.14x = 364 ==========> x == 2600. ANSWER. $2600 invested at 4%; Twice of it, $5200 invested at 5%. CHECK. 0.04*2600 + 0.05*5200 = $364. ! Correct !