The original volume is equal to 248.6 mL.
To find the value of pressure, volume or temperature of a gas after a transformation, one must use the general gas law:
[tex]\frac{P_1 V_1}{T_1} =\frac{P_2 V_2}{T_2}[/tex]
Thus, as the pressure does not change, it is enough to substitute the values in the above formula, such that:
[tex]\frac{V_1}{20}=\frac{373}{30} \\ V_1 = 248.6mL[/tex]
So, the original volume is equal to 248.6 mL.
Learn more about gas law in: brainly.com/question/1190311