FYKOS Year 32 Series 3 Problem 1 — discounted bananas · FYKOS 32 #32.3.1
Physics · mechanics · thermodynamics
Problem
Mikulas put bananas into a carry bag in a grocery store and before he had weighted them, he got an idea. If he fills the bag with helium instead of air, the bananas will weigh less. Mikulas bought the helium in a sale - one CZK for a litre at standard pressure. Calculate the prize of the bananas so that this "bluff" pays off.
Bonus: Find a gas for which it would pay off when the price of bananas is 30 CZK per kilogram. Do not forget to cite references.