Three times Xiaogang's age this year is equal to five times Xiaofang's age. 10 years later, if 4 times of Xiaogang's age is equal to 5 times of Xiaofang's age, what is Xiaogang's age this year?
今年小刚年龄的3倍与小芳年龄的5倍相等．10年后小刚的年龄的4倍与小芳年龄的5倍相等，则小刚今年的年龄是多少岁．
<gadget id="calculator">5 * 10</gadget>
<output>50</output>

<gadget id="calculator">4 * 10</gadget>
<output>40</output>

<gadget id="calculator">50 - 40</gadget>
<output>10</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">5 * (3/5)</gadget>
<output>3</output>

<gadget id="calculator">4 - 3</gadget>
<output>1</output>

<gadget id="calculator">10 / 1</gadget>
<output>10</output>

<result>10</result>