Task: Question Answering
Input (English): Problem: john purchased some shirts and trousers for $ 700. he paid $ 400 less for the shirts than he did for the trousers. if he bought 5 shirts and the cost of a shirt is $ 20 less than that of a trouser, how many trousers did he buy ?
Options: a. 4, b. 5, c. 6, d. 7, e. 11
Output (English): e