An aircraft climbs from sea level to 16,000 ft at 1,000ft per min, the cabin pressurisation is set to climb at 500ft per min to a cabin altitude of 8,000ft. The time taken for the cabin to reach 8,000ft is:
the same time as it takes the aircraft to reach 16,000ft.
half the time it takes the aircraft to reach 16,000ft.
twice the time it takes the aircraft to reach 16,000ft.
three times the time it takes the aircraft to reach 16,000ft.