1997 AMC 8 Problem 16

Below is the professionally curated solution for Problem 16 of the 1997 AMC 8, from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 1997 AMC 8 solutions, or check the answer key.

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Concepts:percentage

Difficulty rating: 1210

16.

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

A=B=CA = B = C

A=B<CA = B \lt C

C<B=AC \lt B = A

A<B<CA \lt B \lt C

B<A<CB \lt A \lt C

Solution:

After the first year, AA's stock's worth goes up to $1001.2=$120 \$ 100 \cdot 1.2 = \$ 120 and BB's goes down to $100.75=$75. \$ 100 \cdot .75 = \$ 75.

After the second year, AA's stock is worth $120.8=$96 \$ 120 \cdot .8 = \$ 96 and BB's is worth $751.25=$93.75. \$ 75 \cdot 1.25 = \$ 93.75.

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

Thus, E is the correct answer.

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