Task: Question Answering
Input (English): Problem: a worker can load one truck in 6 hours. a second worker can load the same truck in 4 hours. if both workers load one truck simultaneously while maintaining their constant rates, how long, in hours, will it take them to fill one truck ?
Options: a. 2.1, b. 2.4, c. 2.7, d. 3.0, e. 3.3
Output (English): b