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

(Problem)
(Solution #1)
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==Solution #1==
 
==Solution #1==
1,1,2,3,5,8,13,21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765
+
The first 20 terms F_n = 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765
  
so ask = 1+  3 + 4 + 7 + 11 + 18 + +29 +47 + 76 + 123 =  <math>\boxed{B 319} </math>.  
+
so ans = 1 +  3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =  <math>\boxed{B: 319} </math>.  
  
 
~[https://artofproblemsolving.com/wiki/index.php/User:Cyantist luckuso]
 
~[https://artofproblemsolving.com/wiki/index.php/User:Cyantist luckuso]

Revision as of 02:52, 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 18

The Fibonacci numbers are defined by $F_1=1,$ $F_2=1,$ and $F_n=F_{n-1}+F_{n-2}$ for $n\geq 3.$ What is\[\dfrac{F_2}{F_1}+\dfrac{F_4}{F_2}+\dfrac{F_6}{F_3}+\cdots+\dfrac{F_{20}}{F_{10}}?\] $\textbf{(A) }318 \qquad\textbf{(B) }319\qquad\textbf{(C) }320\qquad\textbf{(D) }321\qquad\textbf{(E) }322$

Solution #1

The first 20 terms F_n = 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765

so ans = 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 = $\boxed{B: 319}$.

~luckuso

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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