PSLE Maths question. How to solve?

[Mivec9]

From Yahoo Sg:

 

Jim bought some chocolates and gave half of it to Ken. Ken bought some sweets and gave half of it to Jim. Jim ate 12 sweets and Ken ate 18 chocolates. The ratio of Jim

[Jman888]

i guess majority of the parents in singapore (those with kids from 6-13 yr old) are trying to solve this question.... [sweatdrop]

[Contax]

My son told me after he got out of the exam hall that some of his peer has got no time to finish some of the question.Some as many as 5 questions...

 

I just told him to move on and since you have done your best , don't look back and go play balls .

 

 

[Kingcopa]

My son told me after he got out of the exam hall that some of his peer has got no time to finish some of the question.Some as many as 5 questions...

 

I just told him to move on and since you have done your best , don't look back and go play balls .

 

for u

[Vroomtattat]

Must wait for brudder Leslie . . . he's the whizz.

[Vroomtattat]

need to use dunno what bars etc...did it before but kinda forgot it once i mastered algebra..

 

Models . . . they cannot use Algebra yet.

[Windcloud03]

Algebra is taught in Primary school but NOT simultaneous equations, ie they only have one unknown.

 

You can use ALL methods to solve the questions, including algebra. MOE replied to a ST forum letter officially.

 

my solution using only algebra without simultaneous equation.

 

can they use algebra? thought not supposed to do so? where's MOE's reply?

[Josho]

I'll die when my kid taking PSLE next time.... Im poor at all subject especially Math. Now it is not just kids need to be good but parents as well.

 

Not easy...

[Milo]

bro, engage a tutor, a pro one.

[Jamstart]

I think more than 50% of the adults here cant solve this question.

[Josho]

bro, engage a tutor, a pro one.

 

Yeah lo.... i dare not to think 10 years down the road.. how tough the education will be.

[Milo]

Yeah lo.... i dare not to think 10 years down the road.. how tough the education will be.

 

 

dont worry, no matter how tough the education will be, as long as the kids have the right attitude, there will always be assistance n guidance.

[Leslielai]

Tadah

 

If its not clear enough I can further elaborate

 

*edit - sorry, got plotting errors in my first picture

 

Edited October 12, 2009 by Leslielai

[Tunge]

Tadah

 

If its not clear enough I can further elaborate

 

 

 

woohoo u r good

[Josho]

I still very blur on the working sum

 

Why must 12 x 4 + 18?

Sweet is 2 units?

 

Sorry ah.. I am very bad at math... just want to understand more...

Bloody lost.

 

Thanks for the good effort, Leslielai.

 

The amended graph made me even confused.

Edited October 12, 2009 by Josho

[Leslielai]

I still very blur on the working sum

 

Why must 12 x 4 + 18?

Sweet is 2 units?

 

Sorry ah.. I am very bad at math... just want to understand more...

 

Bro,

 

No problem. Here goes

 

1. We start out by plotting the diagram for Jim, with a unit to indicate the amt of sweets he has left + the dotted area indicating that he has consumed 12 sweets.

 

2. Next, since we know that the amount of chocolates he has left is 7 times the sweets he has left. Therefore, 7 units

 

3. Following that, we can now plot Ken's diagram. Bear in mind that he did not consume any sweet at all and that what he has should be what Jim had initially (inclusive of the dotted area representing the 12 he consumed). This time round we use a regular line to include 12, not dotted line as it still exists. In doing so, we can obviously tell that each unit of Ken's sweet or chocolates for that matter is equal to one unit of Jim's, PLUS 12.

 

4. Follow through by drawing 4 times of the above.

 

Recall that since the amt of chocolates Jim has (which remains unchanged) should be equal to the amount Ken had at the first. We'll extend the chocolate diagram for Ken to the same length as Jim's. This represents the 18 Ken has consumed.

 

Since in step 3, the units for Ken is drawn in such a way that every unit of his sweets/chocolate is EQUAL to each unit of Jim's PLUS 12. Therefore, the difference in terms of units between Jim and Ken should equate to all the numerical differences denoted by 12, 12, 12, 12 and 18.

 

The key here is in mapping Ken's model. Each unit in Ken's term is one unit of Jim's plus 12.

Edited October 12, 2009 by Leslielai

[Vroomtattat]

woohoo u r good

 

Give the man a tigerrrrhhhhhh . . . . .

[Kusje]

My son told me after he got out of the exam hall that some of his peer has got no time to finish some of the question.Some as many as 5 questions...

 

I just told him to move on and since you have done your best , don't look back and go play balls .

 

I think a lot of people have been brainwashed to believe that as long as you try hard enough, you will succeed. They end up spending 15 minutes on a stupid 5 mark question that they cannot solve and refuse to move on; these are the ones who end up coming out of the exam hall in tears because they can't finish the paper.

 

Same goes with life. Not everyone can become the POTUS, not everyone can be the next Bill Gates. Everyone should learn about their own capabilities and set reasonable goals instead of setting themselves up for failure.

 

tldr, some people watch too much Forrest Gump.