Answer:
We're told that the chance of landing heads is 2/7, which means that the chance of landing a tail is 5/7.
The chance of rolling each combination then is:
h, h: (2/7) * (2/7) = 4/49
h, t: (2/7) * (5/7) = 10/49
t, h: (5/7) * (2/7) = 10/49
t, t: (5/7) * (5/7) = 25/49
