Task: Question Answering
Input (English): Problem: if 15 students in a class average 75 % on an exam and 10 students average 90 % on the same exam, what is the average in percent for all 25 students ?
Options: a. 80 %, b. 81 %, c. 82 %, d. 83 %, e. 84 %
Output (English): b