Question

3- Interpolando ou inserindo 4 meios aritméticos entre 5 e 20, então a P.A. é:
a)PA(5,10,12,15,18,20)

b) PA(5,8,11,14,17,20)

c) PA(5, 7, 9, 11,13,20)

d) PA(5,10,15,20)

e)n.d.a.​

Answer 1

Resposta:b) PA(5,8,11,14,17,20)

Explicação passo-a-passo:

K=4 meios aritméticos,n=k+2--->n=4+2-->n=6 termos,a1=5,a6=20,r=?

an=a1+(n-1).r

20=5+(6-1).r

20=5+5.r

20-5=5-5+5r

15=5r

r=15/5

r=3

PA(5,8,11,14,17,20)