This question requires the knowledge of two equations from the Hardy-Weinberg Principle. p + q = 1 and p2 + 2pq + q2 = 1 where p = dominant allele, and q = recessive allele. Firstly we know from the question that 30% are non-tasters and so using equation 1, which means all remaining in the population are tasters. So 1 - 0.3 = 0.7 Which means that 70% of the popultation are tasters. Understanding of the equations is required to know that 2pq = the proportion of heterozygous Therefore next, we input values we know into this. 2 x (0.3) x (0.7) = 0.42 This tells us 42% of the population are heterozygous and so 100 - 42 = 58. So 58% of the population are not heterozygous.