First find the total number of baby minks: 30 minks * 6 babies/mink = <<30*6=180>>180 minks
Add this to the number of adult minks: 180 minks + 30 minks = <<180+30=210>>210 minks
Then divide this number in half to find how many aren't set free: 210 minks / 2 = <<210/2=105>>105 minks
Then divide the remaining number of minks by the number of minks per coat to find the number of coats: 105 minks / 15 minks/coat = <<105/15=7>>7 coats
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