Question

A soma dos múltiplos de 5 entre 100 a 2500?

Answer 1

$> resolucao \\ \\ \geqslant progressao \: aritmetica \\ \\ an = a1 + (n - 1)r \\ 2495 = 105 + (n - 1)5 \\ 2495 = 105 + 5n - 5 \\ 2495 = 100 + 5n \\ 2495 - 100 = 5n \\ 2395 = 5n \\ n = \frac{2395}{5} \\ n = 479 \\ \\ = = = = = = = = = = = = = = = = = = = = = \\ \\ \\ sn = \frac{(a1 + an)n}{2} \\ \\ sn = \frac{(105 + 2495)479}{2} \\ \\ sn = \frac{2600 \times 479}{2} \\ \\ sn = 1300 \times 479 \\ \\ sn = 622700 \\ \\ \\ > < > < > < > < > < > < > >$