Northwest Building Products (NBP) manufactures two lumber products from a joint milling process: residential building lumber (RBL) and commercial building lumber (CBL). A standard production run incurs joint costs of $420,000 and results in 90,000 units of RBL and 90,000 units of CBL. Each RBL sells for $13 per unit and each CBL sells for $10 per unit. Required: 1. Assuming that no further processing occurs after the split-off point, how much of the joint costs are allocated to commercial lumber (CBL) on a physical measure method basis