The size of the shoes we wear is usually in "yard" or "centimeter", and the conversion relationship between them is: b=2a-10 (b indicates the number of yards, a indicates the number of centimeters). So what is the size of a 24 cm long shoe using "size" as the unit.
我们所穿鞋的尺码通常用"码"或"厘米"作单位，它们之间的换算关系是：b=2a-10(b表示码数，a表示厘米数)．那么24厘米长的鞋子用"码"作单位是多少码．
<gadget id="calculator">2 * 24</gadget>
<output>48</output>

<gadget id="calculator">48 - 10</gadget>
<output>38</output>

<result>38</result>