A gallon tub costs $55. Ryan anticipated that they would purchase tubs in six different colors - blue, yellow, red, green, white and black. As beginners, Ryan and Jared estimated that, on average, they could produce 400 T- shirts from one gallon of ink, regardless of the actual color combination used on any one individual shirt. Based on this, they estimated that they would need to purchase 15 gallons of ink during their first year of operations. Would the cost of ink be variable or fixed?