docs: update Khan Academy link

Author: vil02

Diff for: en/Basic Math/Average_Mean.md

@@ -59,7 +59,7 @@ Return the value of 22.<u>857142</u> or `23`.
 
 ## Video URL
 
--   [Mean on Khan Academy](https://www.khanacademy.org/math/ap-statistics/summarizing-quantitative-data-ap/measuring-center-quantitative/v/mean-median-and-mode)
+-   [Mean on Khan Academy](https://www.khanacademy.org/math/cc-sixth-grade-math/cc-6th-data-statistics/mean-and-median/v/mean-median-and-mode)
 
 ## Others
 

Diff for: ko/기초 수학/평균값.md

@@ -57,7 +57,7 @@ count = 7
 
 ## 영상 URL
 
-- [Khan Academy](https://www.khanacademy.org/math/ap-statistics/summarizing-quantitative-data-ap/measuring-center-quantitative/v/mean-median-and-mode)
+- [Khan Academy](https://www.khanacademy.org/math/cc-sixth-grade-math/cc-6th-data-statistics/mean-and-median/v/mean-median-and-mode)
 
 ## 기타
 

Diff for: pt-br/Matemática Básica/Média.md

@@ -60,7 +60,7 @@ Retorne o valor de 22 ou `23`.
 
 ## URL do vídeo
 
-- [Média na Khan Academy](https://www.khanacademy.org/math/ap-statistics/summarizing-quantitative-data-ap/measuring-center-quantitative/v/mean-median-and-mode)
+- [Média na Khan Academy](https://www.khanacademy.org/math/cc-sixth-grade-math/cc-6th-data-statistics/mean-and-median/v/mean-median-and-mode)
 
 ## Outros