2009 AMC 8 Problems/Problem 5

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Problem

A sequence of numbers starts with $1$, $2$, and $3$. The fourth number of the sequence is the sum of the previous three numbers in the sequence: $1\plus{}2\plus{}3\equal{}6$ (Error compiling LaTeX. Unknown error_msg). In the same way, every number after the fourth is the sum of the previous three numbers. What is the eighth number in the sequence?

$\textbf{(A)}\  11  \qquad \textbf{(B)}\   20  \qquad \textbf{(C)}\   37  \qquad \textbf{(D)}\   68  \qquad \textbf{(E)}\    99$

See Also

2009 AMC 8 (ProblemsAnswer KeyResources)
Preceded by
Problem 4
Followed by
Problem 6
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All AJHSME/AMC 8 Problems and Solutions