This year, the sum of the ages of Li Lin and his father is 50 years old. After 4 years, his father's age is 2 years younger than three times his age. How much older is Li Lin's father than him?
今年，李林和他爸爸的年龄的和是50岁，4年后，他爸爸的年龄比他的年龄的3倍小2岁，则李林的爸爸比他大多少岁．
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">2 + 50 + 8</gadget>
<output>60</output>

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

<gadget id="calculator">60 / 4</gadget>
<output>15</output>

<gadget id="calculator">3 * 15</gadget>
<output>45</output>

<gadget id="calculator">45 - 2 - 15</gadget>
<output>28</output>

<result>28</result>