A total of $20,000 was invested in two certificates of deposit at simple annual interest rates of 6 percent and 12 percent, respectively. If the total interest on the two certificates was $1,440 at the end of one year, what fractional part of the $20.000 was invested at the higher rate?  Choose the correct choice:
A) 3/8
B) 2/5
C) 1/5
D) 3/5
E) 3/4
x * 6/100 * 1 + (20000 - x) * 12/100 * 1 = 1440   6x - 12x = 144000 - 240000   =&gt; -6x = -96000   =&gt; x = 16000   So 4000/20000 = 1/5   Answer - 1/5
<result>C</result>
A total of $20,000 was invested in two certificates of deposit at simple annual interest rates of 6 percent and 12 percent, respectively. If the total interest on the two certificates was $1,440 at the end of one year, what fractional part of the $20.000 was invested at the higher rate?