Question

a 10 na pg (5,10,20.….)

Answer 1

(5, 10, 20, 40, 80, 160, 320, 640, 1280, 2560,....)
Portanto a10=2560

Answer 2

P.G.(5,10,20...)
a 10 = ?
a 1 = 5 
a 2 = 10
q = a 2 / a 1
q = 10/5
q = 2
a 10 = a 1 . q^n - 1
a 10 = 5 . 2^10 - 1
a 10 = 5 . 2^9
a 10 = 5 . 512
a 10 = 2560