Task: Question Answering
Input (English): Problem: each light bulb at a hotel is either incandescent or fluorescent . at a certain moment , forty percent of the incandescent bulbs are switched on , and eighty percent of the fluorescent bulbs are switched on . if 72 percent of all the bulbs are switched on at this moment , what percent of the bulbs that are switched on are incandescent ? 
Options: a ) 24 % , b ) 16 % , c ) 11 % , d ) 7 % , e ) 5 %
Output (English): c