1993 AJHSME Problems/Problem 3

Problem

Which of the following numbers has the largest prime factor?

$\text{(A)}\ 39\qquad\text{(B)}\ 51\qquad\text{(C)}\ 77\qquad\text{(D)}\ 91\qquad\text{(E)}\ 121$

A. The prime factors of $39$ are $3$ and $13$ . Therefore, the largest prime factor is $13$ .

B. The prime factors of $51$ are $3$ and $17$ . Therefore, the largest prime factor is $17$ .

C. The prime factor of $77$ are $7$ and $11$ . Therefore, the largest prime factor is $11$ .

D. The prime factor of $91$ are $7$ and $13$ . Therefore, the largest prime factor is $13$ .

E. The prime factor of $121$ are $11$ . Therefore, the largest prime factor is $11$ .

So, the answer is $B$

1993 AJHSME (Problems • Answer Key • Resources)
Preceded by Problem 2	Followed by Problem 4
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