First flip
We know the probability of head is 2/7
Since only 2 things can happen, and both cannot happen at once (mutually exclusive), we write
P(tail) = 1 - P(head) = 1 - 2/7 = 5/7
The probability of tail is 1 minus probability of head.
Second flip
You're still using the sam coin, and whatever you got on the first flip doesn't affect your chances of getting head... on the second flip, I mean. So,
2/7; 5/7; 2/7; 5/7
from top to bottom
