Task: Question Answering
Input (English): Problem: martin bought 10 concert tickets, some at the full price of $ 2.00 per ticket, and some at a discounted price of $ 1.60 per ticket. if he spent a total of $ 18.40, how many discounted tickets did he buy ?
Options: a. 3, b. 4, c. 5, d. 6, e. 7
Output (English): b