1993 AMC 8 Problem 3 — Solution | LIVE by Po-Shen Loh

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1993 AMC 8 Problem 3

Attempt Problem 3 of the 1993 AMC 8 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 1993 AMC 8 solutions, or check the answer key.

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3.

Which of the following numbers has the largest prime factor?

$39$

$51$

$77$

$91$

$121$

Answer: B

Concepts:prime factorization prime

Difficulty rating: 660

Solution:

Factoring: $39 = 3 \times 13,$ $51 = 3 \times 17,$ $77 = 7 \times 11,$ $91 = 7 \times 13,$ and $121 = 11 \times 11.$

The largest prime factor among these is $17,$ which is a factor of $51.$

Thus, the correct answer is B .

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