Mix 4 kilograms of fruit sugar at 2.5 yuan per kilogram and 6 kilograms of toffee with a total price of 30 yuan to make assorted candies. What is the unit price of this assorted candies?
将每千克2.5元的水果糖4千克和总价为30元的奶糖6千克混合成什锦糖，这种什锦糖的单价是多少元？
<gadget id="calculator">2.5 * 4</gadget>
<output>10</output>

<gadget id="calculator">10 + 30</gadget>
<output>40</output>

<gadget id="calculator">4 + 6</gadget>
<output>10</output>

<gadget id="calculator">40 / 10</gadget>
<output>4</output>

<result>4</result>