Its a Trick Question...
Of course this could be a trick question.... Changing just 1mB from 1012 to 1011, there is likely to be sufficient 'Sticksion' that the Altimeter would not change its reading at all.
In some aircraft it is not uncommon for the altitude to remain fixed at say 1000ft until you tap the glass, and then it shows you are really at 600ft as you turn onto final... One good reason to judge your landings by visual references rather than the instruments.
This hysteresis is more common on gliders where there is no associated engine vibration to keep the meter constantly shaken.
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