The kindergarten teacher bought as many chocolates, toffees and fruit candies. She gave each child 2 pieces of chocolate, 7 pieces of toffee and 8 pieces of fruit candy. After the distribution, she counted and found that there were 15 pieces of fruit candy left, and the chocolate was exactly three times the size of toffee. So how many children are there in total?
幼儿园老师买了同样多的巧克力、奶糖和水果糖．她发给每一个小朋友2块巧克力，7块奶糖和8块水果糖，发完后清点一下，水果糖还剩15块，而巧克力恰好是奶糖的3倍，那么共有多少个小朋友？
<gadget id="calculator">15 * 3</gadget>
<output>45</output>

<gadget id="calculator">45 - 15</gadget>
<output>30</output>

<gadget id="calculator">7 * 3</gadget>
<output>21</output>

<gadget id="calculator">8 * 3</gadget>
<output>24</output>

<gadget id="calculator">21 - 2 - 24</gadget>
<output>-5</output>

<gadget id="calculator">8 + (-5)</gadget>
<output>3</output>

<gadget id="calculator">30 / 3</gadget>
<output>10</output>

<result>10</result>