How many beers are left in the fridge?

It depends on the fridge. Newer fridges are generally more efficient, so would use less electricity, although size is a definite factor. There should be sufficient information on the fridge to...

It depends. One case of beer contains 24 bottles/cans (330ml) or 12 bottles (1 liter). In any case, 23 bottles or 11 bottles would be left if one beer is taken out of the beer case, respectively.

141 8 ounce beers, it is closer to 160 12 oz beers

A quarter barrel, also known as a pony keg contains 7.75 gallons of beer which is about 82 cans of beer.