Q&A - PSLE Math

[tianzhu]

nsmom:

Anyone has answer key for Catholic high Plim 2010 paper 2? please post if you have one. Thx in advance and best of luck to all our kids..

Hi

For CHS 2010 Maths, please go to this link.

http://www.orlesson.org/orp/10Ma/2010-P6-Math-SA2-CHS.pdf

Best wishes

[tianzhu]

nsmom:

Please help... urgently

Ning and Zong jogged to and fro repeatdly along a straight path in a park between two poins A and B. Ning jogged at a uniform speed of 4 m/s and Zong jogged at a uniform speed of 6 m/s. They started jogging from opposite directions at the same time as shown below.



Ning >>> <<<<<<Zong



A-----------------------------/----------------------------------------/------------------------------------------B

X Y



They first met one another at point X. The second line they met was at point Y.

a) Given that the distance between X and is 160m. Find the distance between A and B.

b) If they started jogging at 8 a.m., how long did they take to meet again for the third time?

Rosyth PLIM (2008)

Hi

As in any Speed type of question, start with a simple diagram. As you need it urgently, I’ll give you some pointers.

Speed

Ning:Zong ------- 4:6 --------2:3

Distance

Ning:Zong ------ 2:3

Draw a line and divide into 5 units.

Ning moves 2 units and Zong moves 3 units.
Distance between A and B ------ 5 units

2 units ------ 160
1 unit -------80

5 units ------- 400

They meet at an interval of 400/ (4+6) or 40 seconds.

Move Ning (2 units)and Zong(3 units) at intervals of 40 seconds along the line.

They meet at 40s(first time), 120s(second time) and 200s(third time).

200/60 -------- 3minute 20 seconds

Best wishes

[tianzhu]

Vanilla Cake:

Hi tianzhu,

Yes, you are right. No need to post worked solutions for these questions. Your slide presentation on Q8 is wonderful and I really enjoy your creativity.
Thks and best wishes.
VC's mum

Hi VC's mum

Good Morning.

You're welcome.

Wishing PC the very best for PSLE 2011.

Best wishes

[tianzhu]

kavisuresh:

Pls help to solve.

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Hi

Hope this helps.

Best wishes

http://farm7.static.flickr.com/6145/6193871980_c0963b8b71_z.jpg\">

[zsqchx]

Please Help!Thanks


Jerry bought four times as many pencils as notebooks and spent a total of $21.60. He spent $2.40 more on the notebooks than the pencils. Given that a notebook costs $3.20 more than a pencil. find the cost of a pencil.

[Brenda10]

zsqchx:

Please Help!Thanks


Jerry bought four times as many pencils as notebooks and spent a total of $21.60. He spent $2.40 more on the notebooks than the pencils. Given that a notebook costs $3.20 more than a pencil. find the cost of a pencil.

Hi, this quesiton look familar! May I know is from which prelim paper ?

[pixiedust]

Let me give it a try :


Jerry bought four times as many pencils as notebooks and spent a total of $21.60. He spent $2.40 more on the notebooks than the pencils. Given that a notebook costs $3.20 more than a pencil. find the cost of a pencil.

spent on pencils = $9.60
spent on notebooks = $12

4U pencils -> $9.60
1U notebook -> $12
1U pencils -> $2.40

$12-$2.4=$9.60
$9.60/$3.20=3

3 notebooks -> $12, each -> $4
cost of each pencil = $0.80

check :
3 notebooks * $4 = $12
12 pencils * $0.80 = $9.60

[tianzhu]

kavisuresh:

Pls help to solve.

1. There are ___ hundredths in 186.42

2. Gerald had $20 more than Tommy at first. After Gerald gave Tommy $60, Gerald had 1/3 as much money as Tommy. Find amt of money Gerald had at first ?

3. Krishnan spent $84 on some plates and 1/3 of remaining money on some cups. If he had 1/5 of original sum of money left, how much did she have at first ?

Hi

Due to time constraints, I’ll give you some pointers instead of drawing models.

Q1) 18642

Q2) You may use MD.

I’ll give you the end MD.

Gerald ------ 1 unit + 40 +20
Tommy ------ 1 unit + 40 +20 + 40 which is equal to 3 times or 3 units.

2 units --------100
1 unit -------50

Gerald -------110 at first.


Q3) You may use MD.

Draw a bar, cut 1 portion to show $84, subdivide the remaining part into 3 small units.

1 unit ------cup
2 units ------left

2 units ------1/5 of original
10 units ------ original sum of money

Hence 7 units ------ 84
1 unit ------- 12

10 units -------120

Best wishes

[zsqchx]

pixiedust:

Let me give it a try :


Jerry bought four times as many pencils as notebooks and spent a total of $21.60. He spent $2.40 more on the notebooks than the pencils. Given that a notebook costs $3.20 more than a pencil. find the cost of a pencil.

spent on pencils = $9.60
spent on notebooks = $12

4U pencils -> $9.60
1U notebook -> $12
1U pencils -> $2.40

$12-$2.4=$9.60
$9.60/$3.20=3

3 notebooks -> $12, each -> $4
cost of each pencil = $0.80

check :
3 notebooks * $4 = $12
12 pencils * $0.80 = $9.60

Thank you very much!

[zsqchx]

Brenda10:

zsqchx:

Please Help!Thanks


Jerry bought four times as many pencils as notebooks and spent a total of $21.60. He spent $2.40 more on the notebooks than the pencils. Given that a notebook costs $3.20 more than a pencil. find the cost of a pencil.

Hi, this quesiton look familar! May I know is from which prelim paper ?

Catholic High 2011 prim Q16