Answer: 0.557
Explanation:
First calculate for the genetic frequencies
A1A1 = 4/70 = 0.057
A2A2 = 24/70 = 0.34
A3A3 = 10/70 = 0.14
A1A2 = 10/70 = 0.14
A1A3 = 2/70 = 0.029
A2A3 = 20/70 = 0.29
Frequency of A2 allele therefore = 0.34 + (0.5×0.14) + (0.5×0.29)
= 0.556
The difference in the answer is due to approximations.