Hardy weinberg problems. please help!?

i'm having a lot of trouble w/ hardy weinberg probs. especially these two.

1. In a sample human population (2000), 45% of the people could not taste the chemical PTC which is a recessive trait. What is the number of individuals that are homozygous dominant, heterozygous, and homozygous recessive. What is the frequency of the dominant allele?

2. A survey revealed that 19% of all Caucasians have very fine textured hair. Assuming that the gene responsible for this trait is recessive, find its frequency and the percentage of Caucacasion who are heterozygous for it.

Thanks!

Hardy weinberg problems. please help!?

a) 45% of the 2000 people have the recessive trait. So...

Let's call the recessive trait aa, the dominant trait AA,

and the heterozygous trait Aa

.45 x 2000 = 900 aa...so, if there's .45 who are recessive..

in order to get the dominant you would need to use the

p^2+2pq+q^2 equation.

.45 sq. root = .67, this would be the a allele frequency, or q

1 - .67 = .33, which would be the A allele frequency, or p

.33^2 = .11, which is the AA

.11 x 2000 = 220 people are AA

To get the heterozygous, multiply 2 by p by q or 2 x .67

x .33 = .44 Aa

So, .44 x 2000 = 880 people are Aa

Good luck :)