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MathNet 2023-part-07 — 187 problems (EN–VI) Question 94

Math Olympiad Vault · MathNet 2023-part-07 — 187 problems (EN–VI)

Question 94

The number $770$ is written on a blackboard. Melody repeatedly performs moves, where a move consists of subtracting either $40$ or $41$ from the number on the board. She performs moves until the number is not positive, and then she stops. Let $N$ be the number of sequences of moves that Melody could perform. Suppose $N = a \cdot 2^{b}$ where $a$ is an odd positive integer and $b$ is a nonnegative integer. Compute $100a + b$.