Question

 Calcule a soma dos 15 primeiros termos da PG (25, 50, 75 ...)​

Answer 1

a1 = 25

q = 50/25 = 2

n = 15

formula - Sn = $a1 (q^{n} - 1)$ / q - 1

S15 = $25 (2^{15} - 1)$ / 2 - 1

S15 = 25 (32.786 - 1)

S15 = 25 (32.785)

S15 = 819.625