The task is to generate the correct answer for a given math problem.

Example Input: Problem: a family pays $ 800 per year for an insurance plan that pays 70 percent of the first $ 1,000 in expenses and 100 percent of all medical expenses thereafter . in any given year , the total amount paid by the family will equal the amount paid by the plan when the family ' s medical expenses total how much ?
Example Output: $ 1,400

Example Input: Problem: two trains each 120 m in length each , are running on two parallel lines in opposite directions . if one goes at the speed of 85 km / h while the other travels at 65 km / h . how long will it take for them to pass each other completely .
Example Output: 10.07 sec

Example Input: Problem: in an examination , a student scores 4 marks for every correct answer and loses 1 mark for every wrong answer . if he attempts all 200 questions and secures 240 marks , the number of questions he attempts incorrectly , is :
Example Output:
112