# Question #ba1dc

##### 1 Answer

Jun 5, 2015

There are four possible sequences of flips. Each is equally likely.

- Heads, Heads
- Heads, Tails
- Tails, Heads
- Tails, Tails

Since since the combination of tails twice in a row is one of four, you can calculate the probability as

This can also be done by multiplying the probability of a particular outcome by the probability for each trial. You know that the probability of tails for each trial is