Difference between revisions of "2020 AIME I Problems"

(Problem 2)
(Problem 3)
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==Problem 3==
 
==Problem 3==
 
A positive integer <math>N</math> has base-eleven representation <math>\underline{a}\underline{b}\underline{c}</math> and base-eight representation <math>\underline1\underline{b}\underline{c}\underline{a},</math> where <math>a,b,</math> and <math>c</math> represent (not necessarily distinct) digits. Find the least such <math>N</math> expressed in base ten.
 
A positive integer <math>N</math> has base-eleven representation <math>\underline{a}\underline{b}\underline{c}</math> and base-eight representation <math>\underline1\underline{b}\underline{c}\underline{a},</math> where <math>a,b,</math> and <math>c</math> represent (not necessarily distinct) digits. Find the least such <math>N</math> expressed in base ten.
 
  
 
[[2020 AIME I Problems/Problem 3 | Solution]]
 
[[2020 AIME I Problems/Problem 3 | Solution]]

Revision as of 15:35, 12 March 2020

2020 AIME I (Answer Key)
Printable version | AoPS Contest CollectionsPDF

Instructions

  1. This is a 15-question, 3-hour examination. All answers are integers ranging from $000$ to $999$, inclusive. Your score will be the number of correct answers; i.e., there is neither partial credit nor a penalty for wrong answers.
  2. No aids other than scratch paper, graph paper, ruler, compass, and protractor are permitted. In particular, calculators and computers are not permitted.
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Problem 1

In $\triangle ABC$ with $AB=BC,$ point $D$ lies strictly between $A$ and $C$ on side $\overline{AC},$ and point $E$ lies strictly between $A$ and $B$ on side $\overline{AB}$ such that $AE=ED=DB=BC.$ The degree measure of $\angle ABC$ is $\tfrac{m}{n},$ where $m$ and $n$ are relatively prime positive integers. Find $m+n.$

Solution

Problem 2

There is a unique positive real number $x$ such that the three numbers $\log_8(2x),\log_4x,$ and $\log_2x,$ in that order, form a geometric progression with positive common ratio. The number $x$ can be written as $\tfrac{m}{n},$ where $m$ and $n$ are relatively prime positive integers. Find $m+n.$

Solution

Problem 3

A positive integer $N$ has base-eleven representation $\underline{a}\underline{b}\underline{c}$ and base-eight representation $\underline1\underline{b}\underline{c}\underline{a},$ where $a,b,$ and $c$ represent (not necessarily distinct) digits. Find the least such $N$ expressed in base ten.

Solution

Problem 4

Solution

Problem 5

Solution

Problem 6

Solution

Problem 7

Solution

Problem 8

Solution

Problem 9

Solution

Problem 10

Solution

Problem 11

Solution

Problem 12

Solution

Problem 13

Solution

Problem 14

Solution

Problem 15

Solution

2020 AIME I (ProblemsAnswer KeyResources)
Preceded by
2019 AIME II
Followed by
2020 AIME II
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
All AIME Problems and Solutions

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