need help please:)

Advice on 11 Plus VR papers and problems

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Pushkin
Posts: 59
Joined: Sat Oct 24, 2009 9:15 am
Location: Gloucestershire

Re: need help please:)

Post by Pushkin »

Hi

The instructions for this type of question are ..."the three numbers in each group are related in the same way."

Doesn't this mean that you have to look at both of the outside numbers in some way to get the middle answer? Looking at just one outside number may get the correct answer in your made up question but it doesn't seem to fit the instructions.
Pushkin
vchin
Posts: 4
Joined: Mon Aug 23, 2010 7:35 am

Re: need help please:)

Post by vchin »

Yes, that being the basic rule, if it is taking longer as in case of 3 operation ones and you want to desperately avoid that, please be convinced as it amounts to doing 1 or 2 operations as opposed to doing 3 in ONLY some of those cases. Then I'm of the view (also like others expressed before, I only elaborated on that with some caution which is not to use add/subtract to get at that quick answer) that we should give it a go to get a quick answer and save that valuable exam time.
vchin
Posts: 4
Joined: Mon Aug 23, 2010 7:35 am

Re: need help please:)

Post by vchin »

vchin wrote:So I guess the moral is not to find (or avoid) quick answers involving just one number with an add/subtract of some constant, until such time there can be such an example to disprove this, but also gives correct answer which is bonus.
Haven't got an ex. where add/subtract rule with one number can turn out to be correct.
vchin wrote:Yes, that being the basic rule, if it is taking longer as in case of 3 operation ones and you want to desperately avoid that, please be convinced as it amounts to doing 1 or 2 operations as opposed to doing 3 in ONLY some of those cases. Then I'm of the view (also like others expressed before, I only elaborated on that with some caution which is not to use add/subtract to get at that quick answer) that we should give it a go to get a quick answer and save that valuable exam time.
I have an ex. to prove this wrong. So all of us who think this is all right, be warned. For this to work, the 3 operations should have been only from 'times' or 'divide', but the big question is we don't know 'that fact', as we're looking for a quick answer. We can only take a gamble, if short of time and not getting any where with 3 operation route.
3[15]40 5[25]50 6[]44 answer is 24. rule is "a times b divided by (a + 5)".
Using quick route, answer cannot be 6 * 5 = 30 because we see 3 * 5 = 15 and 5 * 5 = 25
PS. "a times b divided by 1/5 of b" may also seem right but doesn't work with 6[]44

I'm sorry if i have confused, but hopefully it helps us all to view this one way or the other. All depends on how well they construct a question(and what the question is testing) and we can have lucky escape taking quick/easy route or not.
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