Question

Encontre o valor do Arranjo A (20; 2). *
a) 190
b) 360
c) 380
d) 390

Answer 1

Explicação passo-a-passo:

$\sf A_{20,2}=\dfrac{20!}{(20-2)!}$

$\sf A_{20,2}=\dfrac{20!}{18!}$

$\sf A_{20,2}=\dfrac{20\cdot19\cdot18!}{18!}$

$\sf A_{20,2}=20\cdot19$

$\sf A_{20,2}=380$

Letra C