Southeast u's campus book store sells course packs for $15.00 each, the variable cost per pack is $11.00, fixed costs for this operation are $300,000, and annual sales are 100,000 packs. the unit variable cost consists of a $4.00 royalty payment, vr, per pack to professors plus other variable costs of vo = $7.00. the royalty payment is negotiable. the book store's directors believe that the store should earn a profit margin of 10% on sales, and they want the store's managers to pay a royalty rate that will produce that profit margin. what royalty per pack would permit the store to earn a 10% profit margin on course packs, other things held constant?