function placeAndOrder(orderNumber) {
	console.log("Customer order", orderNumber);
	cookAndDeliverFood(function () {
		console.log("Delivered food order:", orderNumber);
	});
}

//simulating a 5 second operation
function cookAndDeliverFood(callback) {
	setTimeout(callback, 5000);
}

placeAndOrder(1);
placeAndOrder(2);
placeAndOrder(3);
placeAndOrder(4);