Question

CON DESARROLLO POR FA

Answer 1

$a \times 10 + a + a \times 10 + 0 + b \times 10 + b + b \times 10 + 0 = a + b + 140 \\ 10a + a + 10a + 10b + b + 10b = a + b + 140 \\ 21a + 21b = a + b + 140 \\ 21a + 21b - a - b = 140 \\ 20a + 20b = 140 \\ 20(a + b) = 140 \\ a + b = \frac{140}{20} \\ a + b = 7$