2022 AIME II Problems/Problem 14

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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 $b-1$ numbers of $1$ cent stamps will be needed. Using at most $c-1$ stamps of value $1$ and $b$, it is able to have all the values from $1$ to $c-1$ cents.

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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