So far I understand the the payout is 50%.

And also the the number of players is a multiple of the probability...

This must be just to simplify?

And also should allow us to model the thing on n=x right?.

Consider n=x then:

Each player has a 1/x chance of winning, but profits depend on payouts, and there are chances that more than one person *could* win, in which case your profits would be nil or negative. 2 people winning would mean nil, anything more than that would be negative, and anything less than 1 would be 100% profit.

And, now I'm lost... Not even sure where to start...