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Sam runs his own sandwich truck on the U of C campus. The monthly cost of the truck and necessary campus permit is $1,428. Sam spends $5.04 on each sandwich sold, including all of the ingredients, condiments, and paper products. He sells each sandwich for $8.40. a. How many sandwiches does Sam have to sell each month to break even? b. Predict operating income for a month in which Sam sell 2,880 sandwiches. Note: Do not use negative signs with any of your answers