两年前，安迪比贝尔大 $n$ 岁。现在安迪的年龄是贝尔的两倍，两年前贝尔多少岁？

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完整解法

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1. Identify the constant difference in their ages.

The difference in age between two people remains constant over time. Since Andy was $n$ years older than Belle two years ago, Andy is still $n$ years older than Belle now.

2. Formulate an equation for their current ages and solve for Belle's current age.

Let Belle's current age be $B$ .
Andy's current age is $B + n$ .
We are given that Andy is twice Belle's age now:
$B + n = 2B$
$B = n$

3. Find Belle's age 2 years ago.

Belle's age 2 years ago was:
$B - 2 = n - 2$

答案

$n - 2$ (option 3)

AI 分析，可能出错

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两年前，安迪比贝尔大 nnn 岁。 现在安迪的年龄是贝尔的两倍，两年前贝尔多少岁？

完整解法

11

同一知识点的其他题

两年前，安迪比贝尔大 $n$ 岁。现在安迪的年龄是贝尔的两倍，两年前贝尔多少岁？