2011 vcaa exam 1 question

[ducke]

Can some1 please guide me through how to reach the correct answer for core, question 12? The assessor's report wasn't much help. Thanks

[Stick]

If in doubt, test it out. Choose any number (100 makes a good choice) and divide it by the seasonal index. There's your answer.

[Lucid]

Here, read this: http://www.itute.com/wp-content/uploads/2011-vcaa-further-mathematics-exam-1-solutions.pdf

It explains it for you.

[Will T]

Deseasonalised figure = (Actual figure)/(Seasonal Index).
In this case, the seasonal index is 0.8 which is the same as 4/5.

Dividing by 4/5 is the same as multiplying by the reciprocal (5/4) and so this is the same as 5/4 times the Actual figure.
Multiplying something by 5/4 which equals 1.25 is the same as increasing it by 25%.
And so the answer is E.
Hope this helped