Question

Se sabe que a/b =4/7 , además, : 2a +5b=258. Calcula "b"

Answer 1

espero te sirva
$\frac{a}{b} = \frac{4}{7} \\ a = \frac{4}{7} \\ 2a + 5b = 258 \\ 2( \frac{4}{7} ) \: + 5b = 258 \\ \frac{8}{7} b + 5b = 258 \\ \frac{8b + 35b}{7} = 258 \\ \frac{43b}{7} = 258 \\ 43b = 258 \times 7 = 1806\\ b = \frac{1806}{43} = 42 \\ b = 42$