Task: Question Answering
Input (English): Problem: a certain list consists of 21 different numbers. if n is in the list and n is 5 times the average ( arithmetic mean ) of the other 20 numbers in the list, then n is what fraction of the sum of the 21 numbers in the list ?
Options: a. 1 / 20, b. 1 / 6, c. 1 / 5, d. 4 / 21, e. 5 / 21
Output (English): c