Question

The incidence of cystic fibrosis, a recessive genetic disorder in the Caucasian population of United States, is 1 in every 2,500 individuals. Find the number of heterozygous carriers. A.0.0392 B.0.0254 C.0.045

Answer 1

The only equations you need for these types of problems:

p + q =1

p = frequency of the dominant allele in the population
q = frequency of the recessive allele in the population

and p^2 + 2pq + q^2 =1

p^2 = percentage of homozygous dominant individuals
q^2 = percentage of homozygous recessive individuals
2pq = percentage of heterozygous individuals

in the question they tell you that 1/2500 have the disorder..

meaning q^2=1/2500

they're asking you to find 2pq

go!