Respuesta:
60
Explicación paso a paso:
[tex]x + (x \times \frac{20}{100}) = 72 \\ \frac{100x}{100} + \frac{20x}{100} = \frac{7200}{100} \\ 100x + 20x = 7200 \\ 120x = 7200 \\ x = \frac{7200}{120} = 60 \\ \\ \\ comprobamos \\ \\ 60 \times \frac{20}{100} = \frac{1200}{100} = 12 \\ 60 + 12 = 72[/tex]
