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CSSE Maths 2006 Q9 Help

Posted: Thu Aug 16, 2012 11:58 am
by RDDad
Round to the nearest whole number 25.498.
CSSE answer is 25

but i think it should be 26 as 25.498 changes to 25.5 due to 9 and 8 and therefore 25.5 will change to 26?

I would appreciate any help!

Re: CSSE Maths 2006 Q9 Help

Posted: Thu Aug 16, 2012 1:56 pm
by Okanagan
RDDad wrote:Round to the nearest whole number 25.498.
CSSE answer is 25

but i think it should be 26 as 25.498 changes to 25.5 due to 9 and 8 and therefore 25.5 will change to 26?

I would appreciate any help!
You do all the rounding in one go - so with 3 decimal places if it's between .000 and .499 you round down, between .500 and .999 round up.

Or put another way - ignore everything after the first decimal place and just do it as .0 to .4 goes down, .5 to .9 goes up.

Think of all the decimals 25.000 to 25.999 being a queue of people who want tickets to an event - but only half of them can have a ticket (i.e. be rounded up to 26). Is 25.498 in the top 500? Not quite!

Re: CSSE Maths 2006 Q9 Help

Posted: Thu Aug 16, 2012 9:27 pm
by RDDad
Hi Okanagan

Thank you very much for the help.

Really appreciate it.

RDDad