Difference between revisions of "2024 AMC 10B Problems/Problem 24"

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(Solution #1)
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==Problem==
 
==Problem==
 
==Solution #1==
 
Let x,y,z be 3 sides of triangle, r = <math>\frac{s}{p} </math>, 2p = x+y+z , 2s = ax=by=cz =2pr
 
<cmath>s= rs( \frac{1}{a} + \frac{1}{b} +\frac{1}{c} ) </cmath>
 
<cmath> r( \frac{1}{a} + \frac{1}{b} +\frac{1}{c} ) = 1 </cmath>
 
<cmath>r =1,2,3 </cmath>
 
case r=1:
 
<cmath>( \frac{1}{a} + \frac{1}{b} +\frac{1}{c} ) = 1 </cmath>
 
given that 1<=a<=b<=c<=9
 
<cmath> 1 = ( \frac{1}{a} + \frac{1}{b} +\frac{1}{c} )  <= \frac{3}{a} </cmath>
 
<cmath> a <= 3 </cmath>
 
case 1.1 no solution for b,c <cmath>  a= 2 ,  ( \frac{1}{2} + \frac{1}{b} +\frac{1}{c} ) = 1  </cmath> 
 
case 1.2 <cmath>  a= 3 ,  ( \frac{1}{3} + \frac{1}{b} +\frac{1}{c} ) = 1 , (b,c) =(3,3) </cmath>
 
case r=2:
 
<cmath>( \frac{1}{a} + \frac{1}{b} +\frac{1}{c} ) = \frac{1}{2} </cmath>
 
<cmath> (a,b,c) =(6,6,6) </cmath>
 
case r=3:
 
<cmath>( \frac{1}{a} + \frac{1}{b} +\frac{1}{c} ) = \frac{1}{3} </cmath>
 
<cmath> (a,b,c) =(9,9,9) </cmath>
 
answer  <math>\boxed{\textbf{(B) } 3}</math>
 
 
~[https://artofproblemsolving.com/wiki/index.php/User:Cyantist luckuso]
 
  
 
==See also==
 
==See also==

Revision as of 01:44, 14 November 2024

The following problem is from both the 2024 AMC 10B #24 and 2024 AMC 12B #18, so both problems redirect to this page.

Problem

See also

2024 AMC 10B (ProblemsAnswer KeyResources)
Preceded by
Problem 23
Followed by
Problem 25
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
All AMC 10 Problems and Solutions
2024 AMC 12B (ProblemsAnswer KeyResources)
Preceded by
Problem 17
Followed by
Problem 19
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
All AMC 12 Problems and Solutions

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