Question

Alguem pode me ajudar na 68

Answer 1

1mes = x
2mes = x - 20
3mes = $\frac{x-20}{3}$

1mes + 2mes+3mes = 440
$x + x -20 + \frac{x-20}{3} = 440$
$2x + \frac{x}{3} = 440 + 20 + \frac{20}{3}$
$\frac{7x}{3} = \frac{1400}{3}$
$x = \frac{1400}{7} = 200$