Task: Question Answering
Input (English): Problem: a worker can load one truck in 5 hours . a second worker can load the same truck in 4 hours . if both workers load one truck simultaneously while maintaining their constant rates , approximately how long , in hours , will it take them to fill one truck ? 
Options: a ) 1.8 , b ) 2.0 , c ) 2.2 , d ) 2.4 , e ) 2.6
Output (English): c