1. I sampled a population of 100 sulfur-crested cockatoos down under; 50% of them have yellow crests, 25% have bright yellow crests, and 25% have dull yellow crests. These birds are sexually monomorphic, and since both males and females prefer bright yellow crests there is strong sexual selection in this population.

90% of those with bright yellow crests (genotype AA) reproduce

70% of those with a yellow crest (genotype Aa) reproduce

50% of those with a dull yellow crest (genotype aa) reproduce

Determine the proportion of bright crested cockatoos after 3 generations