Условие:
Let a point P move on a straight line according to the score shown on a fair dice that wehrow by the following rules. P starts from the origin O.
• If the score is 6, then P returns to the origin O.
• If the score is 1, 2, or 3, then P moves 1 in a positive direction.
• If the score is 4 or 5, then P moves 1 in a negative direction.
When we throw the dice four times, the probability that the point P is at the origin O is
1-1]
