A hand made paper workshop can hire 8 craftsmen by paying them Rs 400 per person per day. The 9th craftsman demands Rs 450 per day. If this craftsman is hired then all other craftsmen must be paid Rs 450. The marginal resource (labour) cost of the 9th craftsman is
Improve the bracketed part of the sentence. The communities of ants are sometimes very large, (numbered) even upto 500 individuals: and it is a lesson to us that no one has ever yet seen quarrel between any two ants belonging to the same community.