Task: Question Answering
Input (English): Problem: it takes 3 workers a total of 15 hours to build a giant machine with each worker working at the same rate . if 5 workers start to build the machine at 11 : 00 am , and one extra worker per hour is added beginning at 1 : 00 pm , at what time will the machine be complete ? 
Options: a ) 4 : 30 , b ) 4 : 45 , c ) 5 : 00 , d ) 5 : 15 , e ) 5 : 30
Output (English): e