The ratio of stamps collected by Naughty and Xiaoxiao is 4:7. Xiaoxiao has collected 15 more stamps than Naughty. How many stamps has Xiaoxiao collected?
淘气和笑笑收集的邮票张数的比是4：7，笑笑比淘气多收集了15张，笑笑收集了多少张邮票？
<gadget id="calculator">7 - 4</gadget>
<output>3</output>

<gadget id="calculator">15 / 3</gadget>
<output>5</output>

<gadget id="calculator">5 * 7</gadget>
<output>35</output>

<result>35</result>