Instead of sales of 10,000 pair of skis, revised estimates show sales volume at 12,500 pair. At this new volume, additional equipment, at an annual rental of $10,000 must be acquired to manufacture the bindings. This incremental cost would be the only additional fixed cost required even if sales increased to 30,000 pair. (This 30,000 level is the goal for the third year of production.) Under these circumstances, should the Minnetonka Corporation make or buy the bindings? Show calculations to support your answer. Can you tell me how I calculate this? I have no accounting experience and my book isn't helpful.