2003 AMC 10B Problems/Problem 18

Problem 18

What is the largest integer that is a divisor of \[(n+1)(n+3)(n+5)(n+7)(n+9)\] for all positive even integers $n$?

$\textbf{(A) } 3 \qquad\textbf{(B) } 5 \qquad\textbf{(C) } 11 \qquad\textbf{(D) } 15 \qquad\textbf{(E) } 165$

Solution

Since the numbers being multiplied are all odd, $2$ is not a factor of the product, but $3$ and $5$ are since they are 5 consecutive odd numbers. This gives $\boxed{\textbf{(D) } 15}$ as the answer.

See Also

2003 AMC 10B (ProblemsAnswer KeyResources)
Preceded by
Problem 17
Followed by
Problem 19
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All AMC 10 Problems and Solutions

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