The sum of the ages of the two sisters this year is 55 years old. A few years ago, when the elder sister was only as old as the younger sister is now, the younger sister was exactly half of the elder sister's age. How old is my sister?
今年姐妹俩年龄的和是55岁，若干年前，当姐姐的年龄只有妹妹现在这么大时，妹妹的年龄恰好是姐姐年龄的一半．姐姐今年多少岁．
<gadget id="calculator">2 * 55</gadget>
<output>110</output>

<gadget id="calculator">110 - 55</gadget>
<output>55</output>

<gadget id="calculator">110 + 55</gadget>
<output>165</output>

<gadget id="calculator">2 - 1</gadget>
<output>1</output>

<gadget id="calculator">2 + 2 + 1</gadget>
<output>5</output>

<gadget id="calculator">165 / 5</gadget>
<output>33</output>

<result>33</result>