Jamal has a very flexible summer job. He works every day but is allowed to take a day off anytime he wants. His friend Don suggests they take off work on Tuesday to go to the amusement park. The admission charge for the amusement park is $15 per person, and it will cost them $5 each for gas and parking. Jamal loves amusement parks and a day at the park is worth $40 to him. However, Jamal also enjoys his job so much that he would actually be willing to pay $5 per day maximum to do it. If Jamal earns $10 if he works, what is the cost and benefit of going to the park? Should he go to the amusement park?
不知道benefit怎么算,要不要把worth减去机会成本