Answer:
The best estimate of the number of Australians with type AB blood in 2010 is 645,473.
Step-by-step explanation:
Total estimate of Australia'a population = 21,515,754
Percentage of population with AB blood group type = 3%
Number of population with AB blood group type be X


645,472.62 ≈ 645,473
The best estimate of the number of Australians with type AB blood in 2010 is 645,473.