Product YZ2 is made in a production process where machine time is a bottleneck resource. Production of one unit of Product YZ2 takes 0.25 machine hours. The costs and selling price of Product YZ2 are as follows: Materials 10 Labour (0.5 hours) 7 Other factory costs 724 Sales price 30 Profit 6 In a system of throughput accounting, what is the return per factory hour