Suppose that a consumer’s preferences are well behaved in that properties 4-1-4-4 are satisfied and the initial budget constraint is given by 300 = 2X + 4Y. At the initial budget constraint, this consumer purchases 100 units of good X and 25 units of good Y. Suppose the price of X increases to $4 per unit resulting in a new consumption bundle consisting of 60 units of X and 15 units of Y. Then, slope of the inverse demand for good X over this consumption range is