A $500 investment and a $1,500 investment have a combined yearly return of 8.5 percent of the total of the two investments. If the $500 investment has a yearly return of 7 percent, what percent yearly return does the $1,500 investment have?	Choose the most appropriate option:
A) 9 %  B) 10 %  C) 10 5 / 8 %  D) 11 %  E) 12 %

Rationale: "the ratio of investments is 500 : 1,500 = 1 : 3 . the deviation from the average return from $ 500 investment and $ 1,500 investment must be in the ration 3 : 1 . $ 500 investment return has the deviation from the mean of 8.5 - 7 = 1.5 % , thus $ 1,500 investment return must have the deviation from the mean equal to 0.5 % , which means that $ 1 , 500 investment has 8.5 + 0.5 = 9 % yearly return . answer : a ."
Answer: A