Hmm, probability to get a tail is 1/2( am assuming an unbiased coin is being used )
On one throw it is 1/2.
Probability to get more than 6 tails = prob to get 7 tail + prob to get 8 tail
Hopes it helps
Let H be heads and T be tails If you toss a coint eight times this is the possible ways you can get 1 head and 7 tails
{H,T,T,T,T,T,T,T}
{T,H,T,T,T,T,T,T}
{T,T,H,T,T,T,T,T}
{T,T,T,H,T,T,T,T}
{T,T,T,T,H,T,T,T}
{T,T,T,T,T,H,T,T}
{T,T,T,T,T,T,H,T}
{T,T,T,T,T,T,T,H}
There are a total of 8 ways
You could also use the formula for binomial prob
This gives the same answer.
I hope this clear it up.