On Sunday, Dongdong's family of three went to the zoo, the children's tickets were 5.5 yuan each, and the adult tickets were 8.5 yuan each. How much does it cost to buy tickets?
星期日，冬冬一家三口去动物园，儿童票每张5.5元，成人票每张8.5元．买门票一共需要多少钱？
<gadget id="calculator">8.5 * 2</gadget>
<output>17</output>

<gadget id="calculator">17 + 5.5</gadget>
<output>22.5</output>

<result>22.5</result>