AQA A Level Biology Paper 2 2017

https://filestore.aqa.org.uk/sample-papers-and-mark-schemes/2017/june/AQA-74022-QP-JUN17.PDF

In Q10 how would you work out the annual percentage increase please?
I first calculated the number of 30 seconds in a day then multiplied it by 365 so 2880x365=1051200
Then I subtracted it from 5.4x10 to the power of 6 to calculate the change and divided it by 5.4x10 to the power of 6 and multiplied by 100 to get 80.5% but I don't understand why the answer is 19.4% please?

Reply 1

ate3

Im not sure if you've now got the answer to your question but here's how i would have done it:

1) every 30 seconds 1 person develops AD. So that means 2 every minute, scaling that up this means 120 an hour and 2880 per day, which means 1051200 per year. I see that you have already got this so far.
2) the number 1051200 if you read the text is the number that it increases by each year so you would need to add 1051200 to 5.4 million. this equals to 6451200.
3) then basically do what you were doing before:
take this number (6451200) subtract it from 5.4 million, the divide by the original number (so the 5.4 million again) and then times by 100(.

((6451200 - 5400000) / 5400000) * 100 = 19.47% rounded. I think you went wrong as you thought the 1051200 was the new number of people with AD however this was the increase per year.
Hope this helps

(edited 11 months ago)