An aircraft is standing on an airfield 220ft above sea level on a day when the barometric pressure at ground level is 1004 mb. If the pilot sets the altimeter to read 220ft on this day, what will it read if the barometric pressure drops to 992 mb.
An aircraft sets off from airfield A (126 ft above sea level) where the ground pressure is 1010 mb and flies to B (762 ft above sea level) where the ground pressure is 985 mb. If the pilot sets his altimeter (incorrectly) at 26ft at A, what will it read when it lands B?
Atmospheric pressure drops by 1 mbar for every 8.5 m or 27.7 ft of altitude between 0 and 1000 ft, and the differences of your cases from the standard atmosphere are small, so I did not use corrections.