Mix 1 kilogram of toffee and 3 kilograms of fruit sugar into assorted candies, and the unit price is 21.4 yuan. It is known that the total price before and after mixing remains unchanged, and the unit price of fruit candy is 18.6 yuan, so how much is the unit price of milk candy?
用1千克奶糖和3千克水果糖混合成什锦糖，单价是21.4元．已知混合前后的总价不变，且水果糖的单价是18.6元，那么奶糖的单价是多少元？
<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">21.4 * 4</gadget>
<output>85.6</output>

<gadget id="calculator">18.6 * 3</gadget>
<output>55.8</output>

<gadget id="calculator">85.6 - 55.8</gadget>
<output>29.8</output>

<gadget id="calculator">29.8 / 1</gadget>
<output>29.8</output>

<result>29.8</result>