求助 GWD 1-19

Q19: 

A total of $60,000 was invested for one year.  But of this amount earned simple annual
interest at the rate of x percent per year, and the rest earned simple annual
interest at the rate of y percent per year. 
If the total interest earned by the $60,000 for that year was $4,080,
what is the value of x?

(1)
    x = (3/4) y

(2)   The ratio of the amount that earned interest
at the rate of x percent per year to the amount that earned interest at the
rate of y percent per year was 3 to 2.

正确答案是C, 我选的是D。

但其实， 这题我有点没读懂，不太确定在题里，X和Y 是什么关系，两个不同的独立的 interest rate?

望得到高人指点，谢谢。

我也不懂 等答案···