Q&A - PSLE Math

[tianzhu]

Vanilla Cake:

Yes, it really helps a lot! Thanks and you must have spent quite some time drawing out these figures and presenting them.

As you are aware that not all the past years' PSLE Maths questions are available in the published 5-year series, that's why I am compiling the questions and solutions for PSLE Maths 2010 exam from online forums/discussions..

Hi VC

Good Morning.

You’re welcome. I am glad you liked it.

Yes, it took some time; my wife complained I looked more at the MD than at her.

Your compilation of past years questions may be very useful for future kiasu kids, maybe you could call it ----- Vanilla Cake’s way to excel in PSLE Maths.

Don’t worry too much, your sister should do well next year.

Best wishes

[BigDevil]

iFruit:

BigDevil:

http://postimage.org/image/2ryb5fmmc/

I can work out the answer to be a)90 ; b)$16.80. But could someone tell me what is the best method to use to solve this question?

Easier to apparch this as backward problem..

Let the total number of coins at the end = 100u

Thanks! That certainly is faster and neater than what I've come up with!

[mumthebest]

Kumar spent $1729 on a set of encyclopedia. He spend 1/4 ​ of the remainder on a camera and still had 2/5 ​ of his money left. Find the total amount of money he had at first. - (sorry some amendment)

[iFruit]

mumthebest:

Kumar spent $1729 on a set of encyclopedia. He spend 1/4 ​ of the remainder on a camera and still had 2/5 ​ of his money left. Find the total amount of money he had at first. - (sorry some amendment)

Let the remainder after buying encyclopedia = 20u

Monet spent on camera = 5u

Money left = 15u

5u+1729---> 3/5 of money
15u---> 2/5 of money

2(5u+1729) = 3(15u)
35u = 1729x2--->5u = 247x2

total money = 1729+20u = 1729 + 4x247x2 = 3705

[mumthebest]

iFruit:

mumthebest:

Kumar spent $1729 on a set of encyclopedia. He spend 1/4 ​ of the remainder on a camera and still had 2/5 ​ of his money left. Find the total amount of money he had at first. - (sorry some amendment)

Let the remainder after buying encyclopedia = 20u

Monet spent on camera = 5u

Money left = 15u

5u+1729---> 3/5 of money
15u---> 2/5 of money

2(5u+1729) = 3(15u)
5u = 1729x2

total money = 1729+20u = 1729 + 4x1729x2 = 9x1729

The model answer is $3705

[Muffins]

hi mumthebest:


3/4 remainder = 2/5 total

LCM: 6/8 Remainder = 6/15 Total

15 units - 8 units = 7 units

7 units → $1728

$1728/7 = $247

$247 x 15 = $3705

[iFruit]

mumthebest:

iFruit:

[quote=\"mumthebest\"]Kumar spent $1729 on a set of encyclopedia. He spend 1/4 ​ of the remainder on a camera and still had 2/5 ​ of his money left. Find the total amount of money he had at first. - (sorry some amendment)

Let the remainder after buying encyclopedia = 20u

Monet spent on camera = 5u

Money left = 15u

5u+1729---> 3/5 of money
15u---> 2/5 of money

2(5u+1729) = 3(15u)
5u = 1729x2

total money = 1729+20u = 1729 + 4x1729x2 = 9x1729

The model answer is $3705[/quote]Sorry, I made a mistake in the equation

2(5u+1729) = 3(15u)
35u = 2x1729----->5u = 247x2

total money = 1729+20u = 1729 + 4x247x2 = 3705

I corrected the original post but Muffins method is more efficient.

[tiger262]

This thread has benefitted so many PSLE students and parents. It will be most useful if such a thread continues to support Sec-1 Maths also.


I am sure all those who wrote PSLE this year will be glad to have such a thread next year also, as they pursue Sec-1. Does it already exist in this forum? Or will anyone be kind enough to start such a ‘Sec-1 Maths thread’ soon?

Thanks and regards.

[tianzhu]

Hi tiger262


Yes, a thread on secondary school Maths does exist, please follow this link.
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?t=8315&start=0

It is not as active as the primary section; maybe secondary students are more independent.

Best wishes

[tiger262]

tianzhu:

Hi tiger262


Yes, a thread on secondary school Maths does exist, please follow this link.
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?t=8315&start=0

It is not as active as the primary section; maybe secondary students are more independent.

Best wishes

Thank you very much for the prompt reply, Mr. Tianzhu. You are right in saying that the thread may not be as active as the PSLE thread, since Secondary students are more independent.

In my view, one more reason could be that parents are not that closely involved with Sec-1 studies when compared to their involvement in the PSLE stage, although I wonder why.

Thanks and Regards.