// quiz1.rs
// This is a quiz for the following sections:
// - Variables
// - Functions
// Mary is buying apples. One apple usually costs 2 Rustbucks, but if you buy
// more than 40 at once, each apple only costs 1! Write a function that calculates
// the price of an order of apples given the quantity bought. No hints this time!
// Put your function here!
// fn ..... {
// Don't modify this function!