the fact you have to tell someone that it's impossible to predict a 50% 50% chance 100% of the times is kinda sadNo you can't (unless you found a special bug which is pretty unlikely).
no you can't it's serversidedYou can reveal the seed of pseudo random numbers
With every millisecond most often, the seed of generating pseudo-random numbers changes. in conditions when the response time is not close to zero and constantly changingno you can't it's serversided