B3 Darts Manufacturing Ltd manufactures three products Set 1, Set 2 and Set 3, using different quantities of the same materials, one of which is nickel. For costing and reporting purposes, a 'unit' or 'set' is a batch of 100 items. Information about Darts' main three products is as follows: Selling price per unit Set 1 Set 2 Set 3 70 60 144 Cost () per unit: Direct Material, Nickel, at 4 per kg 24 20 Special component Tungsten 0 0 Direct Labour, at 4 per hour 10 12 Variable overhead 6 Total variable cost 40 40 22128 28 32 32 14 90 1,750 3,100 4,000 Weekly demand units units units The quantity of output for component 'Tungsten' will relate directly to that of Set 3. Darts has established that it can only rely on 30,000 hours of labour, and only obtain 55,000 kgs of nickel per week for the foreseeable future. (a) Establish whether labour hours or the material Nickel is the limiting factor for [10] Darts Ltd. (b) Prepare calculations to show optimum weekly output and maximum [10] contribution, based on your decision for requirement (a)