The younger brother's age 9 years ago was the older brother's (1/5), and this year it is the older brother's (1/2), but what is the elder brother's age this year?
弟弟9年前的年龄是哥哥的(1/5)，今年是哥哥的(1/2)，而哥哥今年年龄是多少岁．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">9 * (1/5)</gadget>
<output>9/5 = around 1.8</output>

<gadget id="calculator">9 - (9/5)</gadget>
<output>36/5 = around 7.2</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) - (1/5)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(36/5) / (3/10)</gadget>
<output>24</output>

<result>24</result>