If the average age of 5 people is 25 years old, the youngest of them is 18 years old, and the ages of the 5 people are different. So how old is the oldest?
如果5个人平均年龄是25岁，其中最小的是18岁，且5人年龄都不相同．那么年龄最大的最多是几岁？
<gadget id="calculator">25 * 5</gadget>
<output>125</output>

<gadget id="calculator">18 + 19 + 20 + 21</gadget>
<output>78</output>

<gadget id="calculator">125 - 78</gadget>
<output>47</output>

<result>47</result>