Xiaodong's age this year is his father's age (1/4). After 15 years, Xiaodong's age will be his father's age (5/11). What is Xiaodong's age this year?
今年小东的年龄是爸爸年龄的(1/4)，15年后，小东的年龄是爸爸年龄的(5/11)，今年小东的年龄是多少？
<gadget id="calculator">5 / 11</gadget>
<output>5/11 = around 0.454545</output>

<gadget id="calculator">(5/11) * 15</gadget>
<output>75/11 = around 6.818182</output>

<gadget id="calculator">15 - (75/11)</gadget>
<output>90/11 = around 8.181818</output>

<gadget id="calculator">(5/11) * 4</gadget>
<output>20/11 = around 1.818182</output>

<gadget id="calculator">(20/11) - 1</gadget>
<output>9/11 = around 0.818182</output>

<gadget id="calculator">(90/11) / (9/11)</gadget>
<output>10</output>

<result>10</result>