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GATE 2018 ME (ME1) – Question 62

Production Planning and Control · Aggregate production planning, scheduling and material requirement planning · 2 marks · Numerical answer

Six jobs have (processing time including setup; due date) in days: A (3;8), B (7;16), C (4;4), D (9;18), E (5;17), F (13;19). Using shortest processing time order, average tardiness, to two decimals, is ______ days.

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Correct answer: 6.31 to 6.35

Explanation

SPT order is A,C,E,B,D,F. Completion times are 3,7,12,19,28,41 days. Compare with respective due dates 8,4,17,16,18,19 to obtain nonnegative tardiness 0,3,0,3,10,22. Average is $38/6=6.33$ days.