The shop buys two different kinds of candy, A and B, and the cost ratio is 2:1. It is known that type A candy is 6 yuan per kilogram, and type B candy is 2 yuan per kilogram. , so how much is the cost per kilogram of this assorted sugar?
商店购进甲、乙两种不同的糖果，所用费用之比为2：1，已知甲种糖每千克6元，乙种糖每千克2元，如果把这两种糖混在一起成为什锦糖，那么这种什锦糖每千克的成本是多少元？
<result>3.6</result>