Your classmates from the University of Chicago are planning to go to Miami for spring break, and you are undecided about whether you should go with them. The round­trip airfares are $600, but you have a frequent­flyer coupon worth $500 that you could use to pay part of the airfare. All other costs for the vacation are exactly $900. The most you would be willing to pay for the trip is $1400. Your only alternative use for your frequent­flyer coupon is for your trip to Atlanta two weeks after the break to attend your sister's graduation, which your parents are forcing you to attend. The Chicago­Atlanta round­trip airfares are $450. If the Chicago­Atlanta round­trip air fare were $350, should you use the coupon to go to Miami ?