50% of offspring will have brown eyes
Step-by-step explanation:
A heterozygous individual will have the genotype Rr while an individual who is homozygous recessive will have the genotype rr. A cross between the two will result in offspring with phenotype Rr and rr in the ratio of 1 : 1. This can be observed from the Punnet square attached. The same is the case for the phenotype. The ration of brown eyes to red eyes will be approximately 1 : 1