>>6
Yes and no, the particle can be in more than one states as once, until it colides with another particle (in one and only of those states that it's in). Upon collision the particle becomes one again, and immediately after, it starts travelling in multiple simultaneous states again.
In short, the particle can be in simultaneous states, but only while you're not looking. As soon as you look it becomes one particle again.
Right now this probably sounds like some convenient made up way of dealing with probability. It's not though, there have been experiments performed where two particles have been observed where there should only be one (quantum entanglement). The two particles are shown to have opposite spin and whatnot.