Question

why cooking food takes a place on mountain and lesser than pressure time

Answer 1

At a high altitude there is less atmospheric pressure so water starts to boil at a temperature below 100C so food takes too much time to cook

Answer 2

On mountains, the atmospheric pressure is less. Therefore, the boiling point of water is less than the normal boiling point of water in mountains. Thus cooking in open vessels take long time in mountains. Pressure cooker increases pressure and thus the boiling point of water increases than the normal boiling point of water due to which cooking takes less time.