In order to olve this question we need to apply the Hardy-Weingberg principle, which is simply the bionomial equation p2 + 2pq + q2 to allele frequencies.
First, we obtain the ratios of each genotype. We do that by dividing each genotype frequency/total, so we have:
DOMINANT 50/100 = 0.5
HETEROZYGOUS 40/100=0.4
RECESSIVE 10/100 = 0.1
p - stands for the dominant allele, while q - stands for the recessive allele.
In order to know the frequencies of each allele, we have to consider both the the dominant/recessive frequency and half the heterozygous frequency for each condition (as the heterozygous has a dominant and a recessive allele). So we will have:
Frequency for the dominant allele, 0.5 + 1/2 (0.4) = 0.7
Frequency for the recessive allele, 0.1 + 1/2(0.4) = 0.3
Now, if we want to know the number of copies, we have to multiply the number of individuals that harbor both copies for 2, and then add the number of heterozygotes to each one, as they have only one copy of each allele, so:
DOMINANT = 50 (2) + 40 = 140 copies
RECESSIVE = 10 (2) + 40 = 60 copies