Answer:
50% chance or 1/2.
Explanation:
Let's denote the no freckles allele with f and the freckles allele with F since it is dominant over the no freckles trait.
One parent is homozygous recessive: ff
The other parent is heterozygous (So they have freckles): Ff
Let's do a Punnett Square to calculate the possibility of the offspring having freckles or not. (The Punnett Square may not be perfect)
| F f
f | Ff ff
f | Ff ff
Two of the offspring have Ff, meaning they will have freckles, and two of the offspring have ff, meaning they will not have freckles.
2 out of 4 don't have freckles, which means a 50% chance or 1/2.