If I put a ringing bell inside a jar and seal the jar air tight will I be able to hear the ringing of the bell from outside?
True
When the bell rings the disturbance travels through the air in contact as in the question its mentioned that the jar is sealed air tight. It doesn't say a vacuum is created before. So air is still inside. Now the sound wave through air reaches the glass of the jar and makes the molecules of the jar vibrate. The jar in turn transfers its vibration to the outside environment as it is in contact with it.