If there is market for an indivisible item in which there is for each of the following numbers exactly one supplier whose cost of producing the item are equal to this number: 1,2,3,4,5,6,7,8,9,10. There is also for each of the following numbers exactly one buyer whose value for the item is equal to this number: 2,4,6,8,10,12,14,16,18,20. What are the equilibrium prices in this market?