Difference between revisions of "2006 AIME I Problems/Problem 2"

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== See also ==
 
== See also ==
 
* [[2006 AIME I Problems]]
 
* [[2006 AIME I Problems]]
 +
* [[Combinatorics]]
  
 
[[Category:Intermediate Combinatorics Problems]]
 
[[Category:Intermediate Combinatorics Problems]]

Revision as of 17:15, 18 July 2006

Problem

Let set $\mathcal{A}$ be a 90-element subset of $\{1,2,3,\ldots,100\},$ and let $S$ be the sum of the elements of $\mathcal{A}.$ Find the number of possible values of $S.$

Solution

The smallest S is $1+2+ \cdots +90=91\times45=4095$. The largest S is $11+12+ \cdots +100=111\times45=4995$. All numbers between 4095 and 4995 are possible values of S, so the number of possible values of S is $4995-4095+1=901$.


See also