The average age of Yuanyuan's family of three is 24 years old this year. The age ratio of father, mother and Yuanyuan is 9:8:1. How old is Yuanyuan this year?
圆圆一家三口人今年的平均年龄是24岁，爸爸、妈妈和圆圆今年的年龄比是9：8：1，那么圆圆今年几岁？
<gadget id="calculator">9 + 8 + 1</gadget>
<output>18</output>

<gadget id="calculator">1 / 18</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">24 * 3 * (1/18)</gadget>
<output>4</output>

<result>4</result>