Question

A soma dos múltiplos de 6 entre 80 e 800 é?​

Answer 1

$> \: resolucao \\ \\ \geqslant \: progressao \: \: aritmetica \\ \\ a1 = 84 \\ an = 798 \\ r = 6 \\ \\ = = = = = = = = = = = = = = = = \\ \\ \\ > \: quantidade \: de \: multiplos \: de \: 6 \\ \\ \\ an = a1 + (n - 1)r \\ 798 = 84 + (n - 1)6 \\ 798 = 84 + 6n - 6 \\ 798 = 78 + 6n \\ 798 - 78 = 6n \\ 720 = 6n \\ n = \frac{720}{6} \\ n = 120 \\ \\ = = = = = = = = = = = = = = = = \\ \\ > soma \: dos \: multiplos \: de \: 6 \\ \\ sn = \frac{(a1 + an)n}{2} \\ \\ sn = \frac{(84 + 798)120}{2} \\ \\ sn = \frac{882 \times 120}{2} \\ \\ sn = 882 \times 60 \\ \\ sn = 52920 \\ \\ \\ \geqslant \leqslant \geqslant \leqslant \geqslant \leqslant \geqslant \leqslant \geqslant \leqslant \geqslant \leqslant \geqslant$