Q&A - PSLE Math

[iFruit]

abc_parent:

Hi all

Please help if you can.
Q16) Country A and Country B took part in a Youth Game. From Country A, the ratio of the number of male supporters to the number of female supporters is 5: 6. From Country B, the ratio of the number of male supporters to the number of female supporters was 1:3. The total number of supporters from Country A is 1/4 of the total number of supporters from Country B.
(a) What is the ratio of the number of female supporters from Country A to the number of female supporters from Country B? Express your answer in the simplest forml
(b) After 4985 male supporters from both countries left, the percentage of all the female supporters became 78%. How many more male supporters from country B than country A were there at first?

Ans: 2:11, 5982

Let Country B supporters = 44u (11x4)
Country B males = 11u
Country B Females = 33u

Country A supportes = 1/4(44u) = 11u
A Males = 5u
A Females = 6u

1) Ratio of A females: B Females = 6u:33u = 2:11

2) (11u+5u - 4985) = 22/100 ( 55u - 4985)

1600u -4985 x 100 = 1210u - 22 x 4985

390u = 78 x 4985


number of more males in Country B = 11u - 5u = 6u = (78 x 4985 x 6)/390 = 5982

[tianzhu]

Hi


Hope this helps.

Best wishes.

http://farm5.static.flickr.com/4110/5040921702_62e5e15797_b.jpg\">

[PuzzledboutTHISandTHAT]

There are two bags of stones labelled A and B. In Bag A, there are 350 black stones and 500 white stones. In Bag B, there are 400 black stones and 100 white stones. How many black and white stones should be transferred from bag B to bag A so that 50%of the stonesin bagA and 75%of those in bagB are black? :Can you do the model method?Thks...

[tianzhu]

PuzzledboutTHISandTHAT:

There are two bags of stones labelled A and B. In Bag A, there are 350 black stones and 500 white stones. In Bag B, there are 400 black stones and 100 white stones. How many black and white stones should be transferred from bag B to bag A so that 50%of the stonesin bagA and 75%of those in bagB are black? :Can you do the model method?Thks...

Hi

Your question is similar to one of the earlier posts in this thread.

This question has two unknowns and one is required to use simultaneously equation(SE) to solve it. If a student is comfortable with SE, he/she may use it.

I’ll share how to solve SE with visual representation.

The numbers in the earlier question are different but you should be able to solve your question with the same strategy.

Best wishes.

http://farm5.static.flickr.com/4122/4778205021_8f7608186f_b.jpg\">

[octopusmum]

Hi kancheongmum and tianzhu

Tks for your help, hope there won’t be such questions in psle next week!

[tianzhu]

octopusmum:

Hi kancheongmum and tianzhu

Tks for your help, hope there won't be such questions in psle next week!

Hi

You're welcome.

Best wishes

[abc_parent]

hey Vanilla Cake

all the best for your exams too!

[tianzhu]

Hi


Ali,Bala and charles shared a tin of cookies. Ali took 5/6 of the tin of cookies and 1/3 of a cookie. Bala took 5/6 of the remaining tin of cookies and 1/3 of a cookie. Charles received only 2 cookies. How many more cookies did Ali have than Bala?

Q17 from Rosyth CA1 2009, the answer given in the WS is 60.
Please help to confirm if it is correct.

Best wishes

[Vanilla Cake]

tianzhu:

Hi


Ali,Bala and charles shared a tin of cookies. Ali took 5/6 of the tin of cookies and 1/3 of a cookie. Bala took 5/6 of the remaining tin of cookies and 1/3 of a cookie. Charles received only 2 cookies. How many more cookies did Ali have than Bala?

Q17 from Rosyth CA1 2009, the answer given in the WS is 60.
Please help to confirm if it is correct.

Best wishes

Hi Tianzhu,

This question was first posted by http://www.kiasuparents.com/kiasu/forum/viewtopic.php?t=6373&postdays=0&postorder=asc&start=790 on Mon Apr 12, 2010 8:43 am.
It had been answered by http://www.kiasuparents.com/kiasu/forum/viewtopic.php?t=6373&postdays=0&postorder=asc&start=790 on Mon Apr 12, 2010 9:02 am
and
http://www.postimage.org/image.php?v=gxxlNRS on 12 Apr 2010 13:12

VC's mum

[tianzhu]

Hi VC’s mum


Thank you for your reply.

It really jolted my memory.

What a strange thing to do? I’ve actually answered this question when your daughter requested for it.It’s on pg 138 of this thread.

http://www.kiasuparents.com/kiasu/forum/viewtopic.php?t=280&postdays=0&postorder=asc&start=1370

Well, I’ve to admit I am getting old.

Best wishes