How many Copies does a game have to sell to make mony?

[Reasonable]

Depends on the development costs, marketing, etc.

Basically the second they make a cent over the costs they have made money.

The simple formula would be cost of game divided by cost per copy of game to get copies sold to break even, then add one more copy to add some profit from the whole venture.

But of course its not that simple, as you'd need to factor in how the money from each copy is split to work out when each party involved is going to make money from their investment.