Let Rs. K invested in each scheme
Two years C.I on 20% = 20 + 20 + 20x20/100 = 44%
Two years C.I on 15% = 15 + 15 + 15x15/100 = 32.25%
Now,
(P x 44/100) - (P x 32.25/100) = 528.75
=> 11.75 P = 52875
=> P = Rs. 4500
Hence, total invested money = P + P = 4500 + 4500 = Rs. 9000.