Maths Olympiad Prep

Track / Stage 4 / 139 of 340 #399 of 1964

Problem 399

AMC 12 late, AIME early
Number theory Difficulty 4.8 Find the answer

I1.4 Find the least positive integer dd, such that dc+1000d^{c}+1000 is divisible by 10+c10+c.

A number or a short expression. Fractions can be typed as 3/2, and spacing doesn't matter.

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Official solution

d3+1000 is divisible by 1313×77=1001=1000+13d=1\begin{array}{l}d^{3}+1000 \text { is divisible by } 13 \\ 13 \times 77=1001=1000+1^{3} \\ d=1\end{array}

Source: NuminaMath-1.5, licensed Apache-2.0. Statement reproduced verbatim; metadata (topic, difficulty, ordering) added by this project.