Let's break this down step by step:

A) Write down all the possible outcomes:

When a fair coin is tossed twice, the outcomes can be combinations of heads (H) and tails (T). The total number of outcomes is $2^2 = 4$.

The possible outcomes are:

• HH (both heads)
• HT (first head, second tail)
• TH (first tail, second head)
• TT (both tails)

B) Find the probability of:

1. 2 Heads (HH):

   There is only 1 outcome with 2 heads: HH.

   The probability is: $P(\text{2 heads}) = \frac{\text{number of favorable outcomes}}{\text{total outcomes}} = \frac{1}{4}$

2. Only tails (TT):

   There is only 1 outcome with both tails: TT.

   The probability is: $P(\text{only tails}) = \frac{1}{4}$

Would you like further explanation on this or have any other questions?

Related Questions:

1. What is the probability of getting exactly one head?
2. How many outcomes are possible if the coin is tossed 3 times?
3. What is the probability of getting at least one head?
4. How can you calculate the probability of getting no heads at all?
5. How do probabilities change if the coin is biased?

Tip: The sum of all probabilities for a set of events should always equal 1.