Question

Penni Precisely 分别购买了 $\$ 100$ 的三家公司股票：Alabama Almonds、Boston Beans 和 California Cauliflower。一年后，AA 上涨 $20 \%$ ，BB 下跌 $25 \%$ ，CC 不变。第二年，AA 比前一年下跌 $20 \%$ ，BB 比前一年上涨 $25 \%$ ，CC 仍不变。如果 $A, B$ 和 $C$ 是这些股票的最终价值，那么

Penni Precisely buys $\$ 100$ worth of stock in each of three companies: Alabama Almonds, Boston Beans, and California Cauliflower. After one year, AA was up $20 \%,$ BB was down $25 \%,$ and CC was unchanged. For the second year, AA was down $20 \%$ from the previous year, BB was up $25 \%$ from the previous year, and CC was unchanged. If $A, B,$ and $C$ are the final values of the stock, then

$A = B = C$

$A = B \lt C$

$C \lt B = A$

$A \lt B \lt C$

$B \lt A \lt C$

答案：E

知识点：百分数

难度评级：1210

解答：

第一年后，AA 价值变为，BB 价值变为 $\$ 100 \cdot 1.2 = \$ 120$ $\$ 100 \cdot .75 = \$ 75.$

第二年后，AA 价值为，BB 价值为 $\$ 120 \cdot .8 = \$ 96$ $\$ 75 \cdot 1.25 = \$ 93.75.$

CC 价值仍不变，所以最终顺序是 $B \lt A \lt C.$

所以正确答案是 E。

After the first year, AA's stock's worth goes up to $\$ 100 \cdot 1.2 = \$ 120$ and BB's goes down to $\$ 100 \cdot .75 = \$ 75.$

After the second year, AA's stock is worth $\$ 120 \cdot .8 = \$ 96$ and BB's is worth $\$ 75 \cdot 1.25 = \$ 93.75.$

CC's stock worth remains the same, so the ordering of the stock worths is now $B \lt A \lt C.$

Thus, E is the correct answer.

1997 AMC 8 第 16 题

答案：E

难度评级：1210

解答：

其他年份的第 16 题