2009 PSLE Mathematics

Audioboxing SG

Got this question from somewhere else on the internet:

6/14 of the chairs in a hall are in rows of 13. Half of the chairs are in rows of 7. There are 112 more chairs in rows of 7. The rest of the chairs are stacked up. Find the total number of chairs. (5marks)

Turns out the answer can be easily obtained to be 1568. But then if it is so how can 6/14 of the chairs be rearranged into rows of 13*? I used to do very badly in primary school math because of these extra details that 'tricks' or confuses the student by having them consider extra details that most of the time adds to the confusion! Oh well, no point complaining about PSLE as I got over it aeons ago (there are better things in life than getting good grades, or a well paid job), and the current P6 kids and their parents should too.

*Turns out it wouldn't be a whole number.

charlize SG

I think people need to look at the questions from the viewpoint of a 12 year old kid.

As adults, we can easily rationalise and solve primary school maths questions even if they were tricky because most of us have (hopefully) taken maths up till O levels or higher. Our problem solving skills and mathematical abilities will definitely be higher and more advanced than those of the Primary 6 kid.

Kids will still be kids, regardless of how smart or mature they may seem for their age.

Faced with an exam which they thought they would do well but instead got whacked will hit their morale and confidence hard. It's just the normal way kids will react in these situations.

Mybluemoon SG

Solution

Let Jim's Ratio of Sweets to Chocolates be x

Ratio therefore would be: x : 7x

Let Ken's Ratio of Sweets to Chocolates be Y

Ratio therefore would be: y: 4y

since Jim ate 12 sweets, Ken Ate none.

(x+12)=y ---(1)

therefore 2y = Ken's total sweets

Since Jim did not eat any of his chocolates, Ken ate 18.

(4y+18)= 7x ---(2)

from (1)

x= y-12

sub into (2)

4y+18 = 7(y-12)

4y+18=7y-84

102=3y

y = 34

2y =68 (solved)

honestly, i dun think primary school kids know how to apply algebra to the qn =)

Seowlah SG

A P5 Math Olympiad student is taught how to solve maths questions using simultaneous equations (elimination and substitution methods), form algebraic equation and solve them using all the different solving for x methods by her teacher.

Teachers are very kiasu now.

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