Question

Tom 的年龄为 $T$ 岁，也等于他三个孩子年龄之和。 $N$ 年前，他的年龄是当时三个孩子年龄之和的两倍。求 $T/N$ ？

Tom's age is $T$ years, which is also the sum of the ages of his three children. His age $N$ years ago was twice the sum of their ages then. What is $T/N?$

$2$

$3$

$4$

$5$

$6$

答案：D

知识点：年龄问题一次方程

难度评级：1290

解答：

$N$ 年前 Tom 的年龄为 $T-N$ ，三个孩子年龄之和为 $T-3N$ 。

条件给出 $T-N=2(T-3N)$ ，所以 $T-N=2T-6N$ ，化简为 $5N=T$ 。

因此 $T/N=5$ 。

所以正确答案是 D。

$N$ years ago Tom's age was $T-N,$ and the sum of his three children's ages was $T-3N.$

The condition gives $T-N=2(T-3N),$ so $T-N=2T-6N,$ which simplifies to $5N=T.$

Therefore $T/N=5.$

Thus, the correct answer is D.

2007 AMC 10B 第 12 题

答案：D

难度评级：1290

解答：

其他年份的第 12 题