2021 AMC 12A Fall Problem 1 — Solution | LIVE by Po-Shen Loh

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2021 AMC 12A Fall Problem 1

Attempt Problem 1 of the 2021 AMC 12A Fall below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 2021 AMC 12A Fall solutions, or check the answer key.

All problems are used with official legal permission of the Mathematical Association of America (MAA).

1.

What is the value of $\frac{(2112 - 2021)^2}{169}?$

$7$

$21$

$49$

$64$

$91$

Answer: C

Concepts:factoring perfect square

Difficulty rating: 890

Solution:

Since $2112 - 2021 = 91 = 7 \cdot 13$ and $169 = 13^2,$ the fraction is $\dfrac{(7 \cdot 13)^2}{13^2} = 7^2 = 49.$

Thus, the correct answer is C.

Problem 2#2 →

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