Task: Question Answering
Input (English): Problem: two pipes can fill a tank in 12 minutes and 20 minutes respectively. both pipes are opened together and after some time the first pipe is closed and the tank is full in totally 10 minutes. for how many minutes was first pipe open ?
Options: a. 8 minutes, b. 6 minutes, c. 7 minutes, d. 10 minutes, e. 9 minutes
Output (English): b