In the following question, four groups of three numbers are given. In each group the second and third number are related to the first numberby a Logic/Rule/Relation. Three are similar on basis of same Logic/Rule/Relation. Select the odd one.
7 workers work in a printing press. Each gets paid Rs 450 per day. The 8th worker demands Rs 500 per day. If this worker is hired then all other workers must be paid Rs 500. The marginal resource (labour) cost of the 8th worker is _______.