Kelly Tran, owner of Tulip Time, operates a local chain of floral shops. Each shop has its own delivery van. Instead of charging a flat delivery fee, Tran wants to set the delivery fee based on the distance driven to deliver the flowers. Tran wants to separate the fixed and variable portions of her van operating costs so that she has a better idea how delivery distance affects these costs. She has the following data from the past seven months: (Click the icon to view the data.) Use the high-low method to determine Tulip Time's cost equation for van operating costs. Use your results to predict van operating costs at a volume of 16,500 miles. Let's begin by determining the formula that is used to calculate the variable cost (slope). Variable cost (slope)