Problem 15 Retailers such as Waitrose face the following decision: they can hire cashiers, or create self- checkout terminals, where customers can scan the items themselves. Imagine that Waitrose's production function takes on the form y = f(x1, x2) = 2x1+ x2, where x1 are cashiers and x2 are terminals. Assume that cashiers receive wages of w1 per hour and terminals have a rental rate of W2 per hour. If w1 = 40, and w2 = 10, what is the cheapest way for Waitrose to process 24 payments in an hour? a) x1 = 0; X2 = 24 b) x1 = 12; X2 = 0 c) X1 = 6; X2 = 12 d) x1 = 8; X2 = 8 e) Waitrose is indifferent to any combination of x1 and X2