Mom and Dad took Cheng Cheng and Ming Ming to visit the zoo. Adult tickets are 7.5 yuan per person, and children's tickets are 3.5 yuan per person. How much does it cost to buy tickets?
爸爸妈妈带着程程、明明参观动物园．成人票每人7.5元，儿童票每人3.5元．买门票一共需要多少钱？
<gadget id="calculator">7.5 + 3.5</gadget>
<output>11</output>

<gadget id="calculator">11 * 2</gadget>
<output>22</output>

<result>22</result>