Question

A soma dos múltiplos de 5,de 100 a 1000 é?

Answer 1

Ola Karina

a1 = 100
an = 1000
r = 5
n = ?

termo geral
an = a1 + r*(n - 1)

100 + 5*(n - 1) = 1000
5*(n - 1) = 900
n - 1 = 900/5 = 180
n = 181

soma
Sn = (a1 + an)*n/2 
Sn = (100 + 1000)*181/2 = 99550

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