Maths Olympiad Prep

Track / Stage 4 / 291 of 340 #551 of 1964

Problem 551

AMC 12 late, AIME early
Number theory Difficulty 4.9 Find the answer

(12 points) The six-digit number 201520 \square 15 \square is divisible by 72. What is this six-digit number?

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

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Official solution

【Solution】Solution: If the six-digit number 201520 \square 15 \square can be divided by 72, then the six-digit number 201520 \square 15 \square can be divided by 8,

then 15 口 can be divided by 8,
so 口 =2=2. Then the six-digit number 201520 \square 15 \square can be divided by 9, so 2+0+2+0++1+5+2=10++1+5+2=10+ 口 can be divided by 9, so 口 =8=8,

so this six-digit number is 208152,
Answer: This six-digit number is 208152.

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