Answer:
50%
Explanation:
Let dominant allele be R, and recessive r. Because one is homozygous recessive, they will have the genotype rr. The other will be Rr because he has the dominant trait but his mother is recessive.
Punnett square
[tex]\left[\begin{array}{ccc}Rr&Rr\\rr&rr\end{array}\right][/tex]
