2025 AMC 8 Problems/Problem 4

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Lucius is counting backward by $7$s. His first three numbers are $100$, $93$, and $86$. What is his $10$th number?


Solution

By the formula for the $n$th term of an arithmetic sequence, we get that the answer is $a+d(n-1)$ where $a=100, d=-7$ and $n=10$ which is $100 - 7(10 - 1) = \boxed{\text{(B)\ 37}}$.

~Soupboy0