Answer :
Let the amount invested at 4% be $100X
THEN , the amount invested at 5% WILL BE $200X
Interest earned = 4X + 10X = 266
14X = 266
X = 19
THEN , the amount invested at 5% WILL BE $200X
Interest earned = 4X + 10X = 266
14X = 266
X = 19