Task: Question Answering
Input (English): Problem: working at constant rate , pump x pumped out half of the water in a flooded basement in 7 hours . the pump y was started and the two pumps , working independently at their respective constant rates , pumped out rest of the water in 3 hours . how many hours would it have taken pump y , operating alone at its own constant rate , to pump out all of the water that was pumped out of the basement ? 
Options: a ) a . 10 , b ) b . 12 , c ) c . 34 , d ) d . 18 , e ) e . 24
Output (English): c