Task: Question Answering
Input (English): Problem: a part of certain sum of money is invested at 16 % per annum and the rest at 20 % per annum, if the interest earned in each case for the same period is equal, then ratio of the sums invested is ?
Options: a. 4: 6, b. 4: 9, c. 4: 3, d. 4: 1, e. 5: 4
Output (English): e