Difference between revisions of "2022 AIME II Problems/Problem 14"

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For positive integers <math>a</math>, <math>b</math>, and <math>c</math> with <math>a < b < c</math>, consider collections of postage stamps in denominations <math>a</math>, <math>b</math>, and <math>c</math> cents that contain at least one stamp of each denomination. If there exists such a collection that contains sub-collections worth every whole number of cents up to <math>1000</math> cents, let <math>f(a, b, c)</math> be the minimum number of stamps in such a collection. Find the sum of the three least values of <math>c</math> such that <math>f(a, b, c) = 97</math> for some choice of <math>a</math> and <math>b</math>.
 
For positive integers <math>a</math>, <math>b</math>, and <math>c</math> with <math>a < b < c</math>, consider collections of postage stamps in denominations <math>a</math>, <math>b</math>, and <math>c</math> cents that contain at least one stamp of each denomination. If there exists such a collection that contains sub-collections worth every whole number of cents up to <math>1000</math> cents, let <math>f(a, b, c)</math> be the minimum number of stamps in such a collection. Find the sum of the three least values of <math>c</math> such that <math>f(a, b, c) = 97</math> for some choice of <math>a</math> and <math>b</math>.
  
==Solution==
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==Solution 1==
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Notice that <math>a</math> must equal to <math>1</math>, or else the value <math>1</math> cent isn't able to be represented. At least <math>b-1</math> number or <math>1</math> cent stamps will be needed.
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To be continued
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~[https://artofproblemsolving.com/wiki/index.php/User:Isabelchen isabelchen]
  
 
==See Also==
 
==See Also==
 
{{AIME box|year=2022|n=II|num-b=13|num-a=15}}
 
{{AIME box|year=2022|n=II|num-b=13|num-a=15}}
 
{{MAA Notice}}
 
{{MAA Notice}}

Revision as of 10:55, 19 February 2022

Problem

For positive integers $a$, $b$, and $c$ with $a < b < c$, consider collections of postage stamps in denominations $a$, $b$, and $c$ cents that contain at least one stamp of each denomination. If there exists such a collection that contains sub-collections worth every whole number of cents up to $1000$ cents, let $f(a, b, c)$ be the minimum number of stamps in such a collection. Find the sum of the three least values of $c$ such that $f(a, b, c) = 97$ for some choice of $a$ and $b$.

Solution 1

Notice that $a$ must equal to $1$, or else the value $1$ cent isn't able to be represented. At least $b-1$ number or $1$ cent stamps will be needed.

To be continued

~isabelchen

See Also

2022 AIME II (ProblemsAnswer KeyResources)
Preceded by
Problem 13
Followed by
Problem 15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
All AIME Problems and Solutions

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