How many magnum bottles of wine for 21 people?

It's impossible to say how many magnum bottles of wine you'll need for 21 people without knowing:

* How much wine do you want to serve per person? A standard serving is 5 ounces, but you might want to serve more or less depending on the occasion and type of wine.

* How long will the event last? A longer event will naturally require more wine.

* What type of wine are you serving? Some wines are lighter and people may drink more of them, while others are heavier and people might drink less.

Here's how to figure it out:

1. Determine your desired servings per person: Let's say you want to serve 6 ounces per person.

2. Calculate total ounces needed: 21 people * 6 ounces/person = 126 ounces

3. Convert ounces to liters: 126 ounces / 33.8 ounces/liter = 3.72 liters

4. Determine how many liters are in a magnum: A magnum is 1.5 liters.

5. Calculate the number of magnums needed: 3.72 liters / 1.5 liters/magnum = 2.48 magnums

Round up to the nearest whole number: You'd need 3 magnum bottles to ensure you have enough wine for everyone.

Important Note: This is just a rough estimate. It's always better to have a little extra wine on hand than to run out. It's also a good idea to consider offering non-alcoholic beverages as well.