Task: Question Answering
Input (English): Problem: 15 people can write 90 book in 20 days working 7 hour a day . then in how many day 240 can be written by 72 people ? 
Options: a ) 240 / 9 , b ) 309 / 28 , c ) 100 / 9 , d ) 200 / 9 , e ) 339 / 26
Output (English): c