Task: Question Answering
Input (English): Problem: 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 ?
Options: a. 3 / 8, b. 2 / 5, c. 1 / 5, d. 3 / 5, e. 3 / 4
Output (English): c