Answer:
0.2637
Explanation:
Probability of a tail turning up = x
Probability of an head turning up = 7x
x + 7x = 1
8x = 1
x = (1/8) = 0.125 = P(tail)
7x = (7/8) = 0.875 = P(head)
If the coin is flipped 8 times, the different combo for HEADS and TAILS include
2H, 6T
3H, 5T
4H, 4T
5H, 3T
6H, 2T
(Note that HEADS indicate a minimum of 2 and TAILS indicate a minimum of 2 too)
The probability of each of them can be found Using Binomial distribution
Binomial distribution function is represented by
P(X = x) = ⁿCₓ pˣ qⁿ⁻ˣ
n = total number of sample spaces = 8
x = Number of successes required = 2,3,4,5,6
p = probability of success = probabilty of a head turning up = 0.875
q = probability of failure = probability of a tail turning up = 0.125
when x = 2
P(2H, 6T) = 0.00008177757
when x = 3
P(3H, 5T) = 0.001144886
when x = 4
P(4H, 4T) = 0.010017753
when x = 5
P(5H, 3T) = 0.056099415
when x = 6
P(6H, 2T) = 0.19634795189
Total probability = sum of all of these = 0.2636917836 = 0.2637 to 4 d.p