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maths help,
https://www.elevenplusexams.co.uk/forum/11plus/viewtopic.php?f=2&t=54010
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Author:  adhdad [ Mon Mar 12, 2018 10:27 am ]
Post subject:  maths help,

Adam has cored 11 more goals than Haymond, who in turn has scored 10 more goals than Jhon. If the three boys have scored 91 goals altogether, how many has Haymond scored ?

Is there a technique to anwer these style of questions ? If anyone can help much appreciated. I kind of worked the answer out but would like to explain if to dd in a structured manner.

thankyou all.

Author:  Guest55 [ Mon Mar 12, 2018 12:29 pm ]
Post subject:  Re: maths help,

You could use logic, algebra or a trial and improvement approach.

"Adam has scored 11 more goals than Haymond, who in turn has scored 10 more goals than Jhon. If the three boys have scored 91 goals altogether, how many has Haymond scored ?"

Trial and improvement: Note that 90/3 = 30
Test: John 20, Haymond 30 [20 + 10], Adam 41 [30 + 11] Tota; = 20+ 30+ 41 = 91 Guessed correctly first time!

Logic: Adam scored 11 more than H 91 -11 = 80, John 10 fewer than H 80 + 10 = 90 so if all equal it would be 90 90 /3 = 30

Algebra: let number of H's goals be h
(h + 11) + h + (h - 10) = 91
3h + 1 = 91 etc

Author:  AdamV [ Mon Mar 12, 2018 4:26 pm ]
Post subject:  Re: maths help,

As with lots of similar problems, I would advise the test taker to make sure that they answer the question being asked. I know that sounds obvious, but it is very easy to end up calculating one thing when another is being asked for.
Guest55's algebra approach is good here, it goes directly for the answer, and correctly swaps the information given (Haymond has 10 more than John) into the reverse (J has 10 fewer than H).

I suspect for many taking 11+ it might be easier to convert the information given into algebra thus:
A=H+11
H=J+10
substituting, A = J+10 +11
We know J+10+11 + J+10 + J = 91
So 3J + 31 = 91, and J=20
BUT must not miss the crucial step of getting to what H scored, so 20+10. This is SO easy to miss out under pressure.

If they are comfortable converting properly to algebra form, go for Guest55's more direct method. Otherwise, I tend to aim for the missing value at one end of the "chain" of information, then work back from there.

Author:  Guest55 [ Mon Mar 12, 2018 5:24 pm ]
Post subject:  Re: maths help,

AdamV - algebra like this is NOT part of the Primary curriculum which is why I suggested other routes.

However, I note your post on Venn diagrams - this IS taught at Primary.

Author:  adhdad [ Mon Mar 12, 2018 8:42 pm ]
Post subject:  Re: maths help,

In the end I went with the trial and improvement method as dd seemed to understand it and replicate it well.

thankyou @ guest55
@ AdamV

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