Question

calcule a soma dos multiplos de 5 compreendidos entre 8 e 76

Answer 1

$> \: resolucao \\ \\ \geqslant \: progressao \: \: aritmetica \\ \\ an = a1 + (n - 1)r \\ 75 = 10 + (n - 1)5 \\ 75 = 10 + 5n - 5 \\ 75 = 5 + 5n \\ 75 - 5 = 5n \\ 70 = 5n \\ n = \frac{70}{5} \\ n = 14 \\ \\ = = = = = = = = = = = = = = = = = \\ \\ > \: soma \: dos \: termos \: da \: pa \\ \\ sn = \frac{(a1 + an)n}{2} \\ \\ sn = \frac{(10 + 75)14}{2} \\ \\ sn = \frac{85 \times 14}{2} \\ \\ sn = 85 \times 7 \\ \\ sn = 595 \\ \\ \geqslant \leqslant \geqslant \leqslant \geqslant \leqslant \geqslant \leqslant \geqslant$