Australia's annual birth rate in 2006 was approximately 12.14 per 1000. Given that the 2006 population was about 29 265 000, approximately how many babies were born in 2006?
All help is appreciated
12.14 babies per 1000 persons means $\displaystyle \frac {12.14 \mbox{ babies}}{1000 \mbox{ persons}}$
that means we have $\displaystyle \frac {0.01214 \mbox{ baby}}{1 \mbox{ person}}$
so for each person, we will have 0.01214 babies. so how many babies will we have for 29 265 000 persons?
The question now is whether that is the population before or after the babies were born. So i'll do both for you.
The birth rate is 1,214%
So if it was before the babies were born, the population is at a value of 100% and we need to add 1,214%
By using cross multiplication:
$\displaystyle \frac{100}{101,214} = \frac{29 265 000}{x}$
I find x = 29 620 277,1
So lets say the population would then be 29 620 277 people. Subtract the original value from that. (Or you could just have used 1,214 instead of 101,214)
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If that was after the babies were born, then the population is now at 100% + 1,214% = 101,214% and then we need to find what the population was at 100% to find the original amount of people, so that we can find the number of babies that were born.
$\displaystyle \frac{100}{101,214} = \frac{x}{29 265 000}$
x = 28 913 984 (I rounded it like above)
Now subtract this from the initial value to get the number of babies that were born.