OK, here's what i've got so far:

Let X = win
Let O = loss

Possible outcomes for Team A:

1. X X (25%)
2. X O (25%)
3. O X (25%)
4. O O (25%)

Possible outcomes for team B to progress under scenario (all other outcomes result in failure):

1. 0%
2. X X (25%)
3. X X (25%)
4a. X O (25%)
4b. O X (25%)
4c. X X (25%)

However scenario's 2, 3, 4a & 4b result in a draw = coin toss

Possible outcomes for team B after coin flip (assuming they win the coin flip):

1. 0%
2. 0.25*0.5 = 12.5%
3. 0.25*0.5 = 12.5%
4a. 0.25*0.5 = 12.5%
4b. 0.25*0.5 = 12.5%
4c. 25%

Probability of qualification = 67.5%

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