Hardy Weinberg

Can someone explain how the answer is 32% for question 7.5 (page 23 of: https://filestore.aqa.org.uk/sample-...2-QP-JUN17.PDF).

I initially tried using p=0.6 and q=0.4 to find 2pq, but got 0.48 which is incorrect.

(Reposted this since accidentally posted first thread in the wrong forum)

Can someone explain how the answer is 32% for question 7.5 (page 23 of: https://filestore.aqa.org.uk/sample-...2-QP-JUN17.PDF).

I initially tried using p=0.6 and q=0.4 to find 2pq, but got 0.48 which is incorrect.

(Reposted this since accidentally posted first thread in the wrong forum)

Well looking from your posts I found the question and got the answer.

This question did get me thinking because it's usually not what I see since I do OCR but all it requires is a little bit of application.

It says that the only plants produced are green and yellow fruit, therefore we can get rid of an A (dominant) anywhere as there's no white so we only have a,B,b alleles left. It also tells us that 0.36 are yellow (which is a combination of dominant and recessive allele) therefore we know that q^2 = 1-0.36 = 0.64 as to get green you would need to have all recessive (aabb).

Using q^2 = 0.64 you just square root to get q = 0.8 and calculate p = 1-0.8 = 0.2 so now that you have p and q you can just use the 2pq to get 2 x 0.2 x 0.8 = 0.32

Hope that helps.

Edit: I did have to use Figure 7 to kind of visualise what was going on and I think you should too.