Hardy-Weinberg equation help needed

From paper 2, 2018:
10% of the population on the Pacific island of Pingelap are affected by complete achromatopsia (which is caused by an autosomal recessive allele). Use the Hardy-Weinberg equation to calculate the percentage of this population who are heterozygous for this disorder.

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

10% = q^2
√0.1 = 0.31 = q
1 - 0.31 = 0.69 = p
0.69^2 = 0.47 = p^2
2pq = 2 x 0.1 x 0.47 = 0.094
Answer: 9.4%

Mark scheme says accept answers from 42-44%. Where did I go wrong? Should the 10% be q rather than q^2?
Thanks!

You need to use the rest of the information in the question. This is a comprehension question so you must use information from the passage to help you.

It says 1 in 40000 are affected. I would go through the answer but it would be more of an impact if you tried it again using that info.

If you still dont understand, let me know and I will explain it.

I did consider that, but the text says "...with only one in 40 000 being affected. However on the Pacific island of Pingelap ten percent of the population are affected." I assumed the "however" indicates that this is not a situation with one in 40 000 being affected?

Hey, you made a very minor mistake when calculating the final result.
You seem to have used p^2(0.47) instead of p(0.69) and q^2(0.1) instead of q(0.31) in 2*p*q. So 2*q^2*p^2. If you calculate 2 * 0.31 * 0.69 the result is 0,4278 which is correct.

Hey, you made a very minor mistake when calculating the final result.
You seem to have used p^2(0.47) instead of p(0.69) and q^2(0.1) instead of q(0.31) in 2*p*q. So 2*q^2*p^2. If you calculate 2 * 0.31 * 0.69 the result is 0,4278 which is correct.

From paper 2, 2018:
10% of the population on the Pacific island of Pingelap are affected by complete achromatopsia (which is caused by an autosomal recessive allele). Use the Hardy-Weinberg equation to calculate the percentage of this population who are heterozygous for this disorder.

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

10% = q^2
√0.1 = 0.31 = q
1 - 0.31 = 0.69 = p
0.69^2 = 0.47 = p^2
2pq = 2 x 0.1 x 0.47 = 0.094
Answer: 9.4%

Mark scheme says accept answers from 42-44%. Where did I go wrong? Should the 10% be q rather than q^2?
Thanks!

From paper 2, 2018:
10% of the population on the Pacific island of Pingelap are affected by complete achromatopsia (which is caused by an autosomal recessive allele). Use the Hardy-Weinberg equation to calculate the percentage of this population who are heterozygous for this disorder.

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

10% = q^2
√0.1 = 0.31 = q
1 - 0.31 = 0.69 = p
0.69^2 = 0.47 = p^2
2pq = 2 x 0.1 x 0.47 = 0.094
Answer: 9.4%

Mark scheme says accept answers from 42-44%. Where did I go wrong? Should the 10% be q rather than q^2?
Thanks!