(picture is provided)
a 2010 estimate of australia's population is 21.515.754
which is the best estimate of the number of australians with type o blood in 2010?
a)645,473
b)2,151,575
c)8,175,987
d)10,542,719

we know that

The number estimate of Australia's population with type O blood in is of the total estimate  

So

to find the best estimate of the number of australians with type O blood in

Multiply  the total Australia's population estimate by the percentage with type O blood

therefore

the answer is

the best estimate of the number of australians with type O blood in is the option

D)10,542,719

i think it would be 42cm