Question

Tyrone 有 $97$ 颗弹珠，Eric 有 $11$ 颗弹珠。之后 Tyrone 给了 Eric 一些弹珠，使得最后 Tyrone 的弹珠数是 Eric 的两倍。Tyrone 给了 Eric 多少颗弹珠？

Tyrone had $97$ marbles and Eric had $11$ marbles. Tyrone then gave some of his marbles to Eric so that Tyrone ended with twice as many marbles as Eric. How many marbles did Tyrone give to Eric?

$3$

$13$

$18$

$25$

$29$

答案：D

知识点：一次方程比与比例

难度评级：960

解答：

设 Eric 最后有 $x$ 颗弹珠，则 Tyrone 最后有 $2x$ 颗。

总弹珠数为 $97 + 11 = 108$ ，所以 $3x = 108$ $x = 36.$

因此 Tyrone 最后有 $36 \cdot 2 = 72$ 颗弹珠，他给出了 $97 - 72 = 25$ 颗。

所以正确答案是 D。

Let $x$ be the number of marbles that Eric ends up with. Then Tyrone ends up with $2x.$

The total number of marbles is $97 + 11 = 108,$ so $3x = 108$ $x = 36.$

Then, Tyrone ends up with $36 \cdot 2 = 72$ marbles. This means he has to give away $97 - 72 = 25$ marbles.

Thus, D is the correct answer.

2010 AMC 10A 第 3 题

答案：D

难度评级：960

解答：

其他年份的第 3 题