Question

Na PA(3+X, 10-X, 9+X,...) a razao vale:
a)x
b)3+x
c)3
d)2
e)6

Answer 1

(3+x) + (9+x) / 2 = (10-x)

3 + x + 9 + x = 2 * (10-x)
12 + 2x = 20 - 2x
2x + 2x = 20 - 12
4x = 8
x = 8 / 4 
x = 2


P.A. ( 5, 8, 11 )

r = a2 - a1
r = 8 - 5
r = 3

Resposta: Letra C.