Answer:
0.25. or 1/4
Step-by-step explanation:
The probability that the first coin will be heads is 0.5. The probability that the second coin will be heads is 0.5. So the probability that the first two coins will be heads is 0.5 * 0.5 = 0.25.
Since the third flip can be either heads or tails, this has a probability of 1.0.
So the probability you want is 0.25 * 1.0 = 0.25. (or if you want a fraction it is 1/4)