Task: Question Answering
Input (English): Problem: a can finish a work in 18 days and b can do the same work in half the time taken by a. then, working together what part of the same work they can finish in a day ?
Options: a. 1 / 2, b. 1 / 3, c. 1 / 6, d. 2 / 5, e. 2 / 9
Output (English): c