Respuesta :
80 + 50x = 70x
80 + 50x - 50x = 70x -50x
80 = 70x - 50x
80 = 20x
80/20 = 20x/20
x = 4 hours
80 + 50x - 50x = 70x -50x
80 = 70x - 50x
80 = 20x
80/20 = 20x/20
x = 4 hours