Answer/Explanation:
(F) => dominant allele for presence of freckles
(f) => recessive allele for no freckles
Since Jake has freckles while his sister has no freckles, therefore:
Jake's dad must be => (ff) (this is the only instance the recessive trait of no freckle can manifest)
Jake's mum would be => (Ff)
Let's complete the Punnett square that shows Jake's family:
Dad------|---f---|---f---|
Mum--F-| Ff | Ff
----------f-| ff | ff
(ff) × (Ff) - Jake's Parent
Ff - Jake
ff - Jake's sister