Answer:
1/4
Explanation:
Flip a fair two sided coin 4 times, the probability the first or last flip is a tail is
P = (1/2) x 1 x 1 x (1/2) = 1/4
(The probability of getting tail in first flip = 1/2, in the 2nd and 3rd flip, tail and head are both accepted, the probability of getting tail in last flip = 1/2)
Hope this helps!