8 A game uses an unbiased die with faces numbered 1 to 6 . The die is thrown once. If it shows 4 or 5 or 6 then this number is the final score. If it shows 1 or 2 or 3 then the die is thrown again and the final score is the sum of the numbers shown on the two throws.

1. Find the probability that the final score is 4 .
2. Given that the die is thrown only once, find the probability that the final score is 4 .
3. Given that the die is thrown twice, find the probability that the final score is 4 .