Helmer's Rockers manufactures two models, Standard and Premium, Weekly demand is estimated to be 100 units of the Standard Model and 80 units of the Premium Model. The following per unit data apply: Standard Premium $20 Contribution margin per unit Number of machine-hours required The contribution per machine-hour is $24 for Standard, $20 for Premium $4 for Standard, 55 for Premium O $18 for Standard, $16 for Premium $144 for Standard, S80 for Premium