Q&A - PSLE Math

[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.

[Muffins]

I guess it's because they are worried about which school their child would go to, and in Sec 1, when they are alrea in their school, it's not as important...

[SLeng]

Hi Vanilla Cake and Parents,


Any clues where can I find past years PSLE exam questions for English, Maths, Science and Chinese ?

[tianzhu]

SLeng:

Hi Vanilla Cake and Parents,


Any clues where can I find past years PSLE exam questions for English, Maths, Science and Chinese ?

Hi

You can buy the books from Popular Bookstore.
http://www.seab.gov.sg/psle/pslePublications.html

Best wishes