Dang.....I hate typing in my answer when I cannot see the question on my screen...I got the turn 3 backwards......so here it goes a gain.....
He has two option roll flip flip or roll roll flip
1st roll has a 2/6 chance of being a 1 or a 2 2/6 = 1/3
then he flips a coin and has a 1/2 chance it is a HEADS (so he would flip coin again turn 3)
He has a 4/6 chance of NOT rolling a 1 or a 2 ...... which means turn 2 would be a roll again
then he has a 2 out of 6 (1/3 chance of rolling a 1 or a two) which makes turn 3 a coin flip
1/3 * 1/2 + 4/6 * 1/3 = 1/6 + 4/18 = 7/18 chance of coin flip on turn 3
This is my first answer that was a WRONG answer:
Well.....no one else has posted an answer to this....so I will make my usual probability-guess at it!
He has 2 out of 6 chance of rolling a 1 or a 2 on the die...... 2/6 = 1/3
then when he flips the coin, he has a 1/2 chance of tails (which would make turn 3 a roll of the die)
He has a 4/6 chance of NOT rolling a 1 or a 2 (which means he ROLLS again)
His second turn will be a roll.... and he has a 4/6 chance this will NOT be a 1 or a 2...
which would make turn 3 a roll of the die
so
1/3 x 1/2 + 4/6 * 4/6 = 1/6 + 16/36 = 22/36 = 11/18 chance turn 3 will be a roll (??)