Door Puzzle Solution

Well the solution to this puzzle is simple. Just think mathematically and you will get the answer.

Let's take the first scenario

You choose one of the door. So probability of getting the jackpot - 1/3.

Let's say that the jackpot is in Door no 1 and you choose Door no 1. So the angel will either open door no 2 or door no 3. Let's look at the sample space of this Puzzle.

                         Door1                                     Door2                             Door3
Case 1 :            Jackpot                                   Goat                                Goat
Case 2 :            Goat                                     Jackpot                              Goat
Case 3 :            Goat                                       Goat                              Jackpot

Now you have chosen to stick with door 1 so your chances of winning will be 1/3.
Now if you decide to change the door.
Let's say again you have chosen Door No 1 initially so the Angel will open Door 3 if it's the second case and if you switch you will win the jackpot. Similarly if it's Case 3 then Angel will open Door No 2 and if you switch you will win. So chances of winning the jackpot if you switch is 2/3.

Hence it is advisable to switch.