AMC 8 1990 Problem 21
AMC8 1990 年第 21 题
数列与规律★★★★☆
Problem A list of 8 numbers is formed by beginning with two given numbers. Each new number in the list is the product of the two previous numbers. Find the first number if the last three are shown:
\text{\underline{\hspace3 mm?\hspace3 mm}\hspace1 mm,\hspace1 mm \underline{\hspace7 mm}\hspace1 mm,\hspace1 mm \underline{\hspace7 mm}\hspace1 mm,\hspace1 mm \underline{\hspace7 mm}\hspace1 mm,\hspace1 mm \underline{\hspace7 mm}\hspace1 mm,\hspace1 mm\underline{\hspace2 mm16\hspace2 mm}\hspace1 mm,\hspace1 mm\underline{\hspace2 mm64\hspace2 mm}\hspace1 mm,\hspace1 mm\underline{\hspace1 mm1024\hspace1 mm}}
一个包含 8 个数的列表由两个给定的数开始形成。列表中每个新数都是前两个数的乘积。已知最后三个数如图所示，求第一个数。 \text{\underline{\hspace3 mm?\hspace3 mm}\hspace1 mm,\hspace1 mm \underline{\hspace7 mm}\hspace1 mm,\hspace1 mm \underline{\hspace7 mm}\hspace1 mm,\hspace1 mm \underline{\hspace7 mm}\hspace1 mm,\hspace1 mm \underline{\hspace7 mm}\hspace1 mm,\hspace1 mm\underline{\hspace2 mm16\hspace2 mm}\hspace1 mm,\hspace1 mm\underline{\hspace2 mm64\hspace2 mm}\hspace1 mm,\hspace1 mm\underline{\hspace1 mm1024\hspace1 mm}
- A.
- B.
- C.1
- D.2
- E.4
正确答案 · Correct Answer
B
解析 · Solution
解析整理中
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