a) Explain why mrp may be described as a 'push' system (6 marks) (6 marks) (b) The gross demand for an item over a ten week mrp planning horizon is: Week 1 2. 3 4 5 6 7 8 9 10 Demand 35 40 28 56 0 40 52 45 24 30 There are currently 40 parts on hand. The cost per setup is estimated to be 300 and the holding cost is 3.50 per unit per week. The lead time is one week. For each of the following lot sizing rules determine the planned order release schedule and calculate the total variable cost: (1) lot for lot, (ii) economic time cycle. Comment on the costs obtained. You may use Fig Q.B7 in your answer. (Make sure you write your registration number and seat number on it and include it with your answer book.) (8 marks) - Many argue that mrp systems have not produced the expected benefits, especially in relation to inventory reduction and customer service improvement. Discuss the principal problems with mrp that have led to this view. (6 marks)