In genetics, incomplete dominance occurs when heterozygous individuals have a phenotype that is intermediate between two possible homozygous genotypes. For example, suppose that in a particular diploid, annual plant, flower color is determined by a single gene with two possible alleles: the dominant allele R, and the recessive allele r. In this plant,

• RR individuals have red flowers
• Rr (and rR) individuals have pink flowers
• rr individuals have white flowers

Suppose that 30% of the plants have red flowers and 55% have pink flowers. What proportion of the plants have white flowers?