Combinari - exercitiu rezolvat 4

C ²₁₀  + C ⁸₁₀   = ?

(combinari de 10 luate cate 2 plus combinari de 10 luate cate 8)

Aplicam formula combinarilor: combinari de n luate cate k si rezulta:

C ²₁₀   + C ⁸₁₀   => 10! / 2!(10 - 2)! + 10! / 8! (10 - 8)!

=> 10! / 2! * 8! + 10! / 8! * 2!

=> 8! * 9 * 10 / 2! * 8! + 8! * 9 * 10 / 8! * 2!

=> 9 * 10 / 1 * 2   + 9 * 10 / 1 * 2

=> 9 * 5  + 9 * 5

=> 45  + 45

=> C ²₁₀  + C ⁸₁₀   = 90

Verifica daca ti-a dat rezultatul corect cu CALCULATORUL DE COMBINARI


Exercitii rezolvate combinari

Probleme si exercitii rezolvate clasa a-X-a

Probleme si exercitii rezolvate