The relation between the volume, pressure and temperature of gases is shown using the following equation: (pressure x volume)1 / temperature1 = (pressure x volume)2 / temperature2 This relation is actually established by combining the three gas laws (Boyle's, Charles's and Gay-Lussac's)
At constant pressure, (volume/temperature)1 = (volume/temperature)2 128/20 = v2/40 Volume = 256 ml
