Jabarkan r2 = 0.25 dari Prinsip Hardy–Weinberg

(p2 + 2pr) + r2 = (0.24) + 0.25 = 0.49

(p + r)2 = (0.7)2

p + r = 0.7

p + 0.5 = 0.7

p + q + r = 1

0.2 + q + 0.5 = 1

q2 + 2qr = (0.3)2 + 2(0.3)(0.5) = 0.09 + 0.3 = 0.39

2pq = 2(0.2)(0.3) = 0.12

jadi golongan darah B = 39% x 5.000 = 1.950 orang serta AB = 12% x 5.000 = 600 orang.