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Pls help, thanks

Academic support for Primary 5

Post
by **Suz855** » Mon Oct 11, 2010 11:45 am

Pls help, thanks

- Vanilla Cake
- BlackBelt
**Posts:**870**Joined:**Thu Oct 16,

Post
by **Vanilla Cake** » Mon Oct 11, 2010 12:28 pm

Suz855 wrote:Pls help, thanks

There is missing information as you don't see the letters R and S of the triangle in the picture. Most likely, it was erased away with the letters R and S unintentionally and the important information that base of the triangle PRS has the measurement of 9 cm ie RS = 9 cm.

With this important information that RS = 9 cm, here's the solution:

Area of ΔPRS = ½x(12+4)x9= 72 cm²

(a) Area of shaded part = 72/8x7 =

Area of rectangle = (129+63) cm² = 192 cm²

Length of rectangle = 192÷12=16 cm

12/16x100% = 75%

(b) Breadth of the rectangle as a percentage of the length of the rectangle =

Mods: Pls merge this post with Q&A - PSLE - Maths.

Thks.

Post
by **Suz855** » Mon Oct 11, 2010 2:01 pm

Thanks VC,

I was thinking along using the ratio given.

Since the shaded part is 7 and given that area of the triangle is 8, the unshaded triangle at the tip will be 1 vs the complete triange as 8.

Taking the height of whole triangle as 16 and the height of the unshaded triangle as 4, the base of the triangle should have the ratio of 1 : 2 which will bring us to area of triange as 32 or 64cm2 and the shaded portion as 28 or 56cm2.....

However probably you are right that the base of 9cm might already been given thus making this a simple area of triangle question instead of a more challenging one

I was thinking along using the ratio given.

Since the shaded part is 7 and given that area of the triangle is 8, the unshaded triangle at the tip will be 1 vs the complete triange as 8.

Taking the height of whole triangle as 16 and the height of the unshaded triangle as 4, the base of the triangle should have the ratio of 1 : 2 which will bring us to area of triange as 32 or 64cm2 and the shaded portion as 28 or 56cm2.....

However probably you are right that the base of 9cm might already been given thus making this a simple area of triangle question instead of a more challenging one

Post
by **ck123** » Fri Oct 22, 2010 3:49 pm

Hi anyone

Please help with the following questions:

1) Zara had 70 more dresses than skirts. She sold 3/4 of the dresses and 3/5 of the skirts. She sold 126 more dresses than skirts. What fraction of the remaining clothes that Zara had were skirts?

2) A seamstress had some white and some black buttons. 60% of the buttons were white. He bought another 120 buttons. Now, the percentage of white buttons became only 40% of the total. How many white buttons did he have at first?

Thanks a lot...

[/img][/list]

Please help with the following questions:

1) Zara had 70 more dresses than skirts. She sold 3/4 of the dresses and 3/5 of the skirts. She sold 126 more dresses than skirts. What fraction of the remaining clothes that Zara had were skirts?

2) A seamstress had some white and some black buttons. 60% of the buttons were white. He bought another 120 buttons. Now, the percentage of white buttons became only 40% of the total. How many white buttons did he have at first?

Thanks a lot...

[/img][/list]

Post
by **Brenda10** » Fri Oct 22, 2010 4:14 pm

ck123 wrote:Hi anyone

Please help with the following questions:

2) A seamstress had some white and some black buttons. 60% of the buttons were white. He bought another 120 buttons. Now, the percentage of white buttons became only 40% of the total. How many white buttons did he have at first?

Thanks a lot...

[/img][/list]

Hi, dd working for Q2)

W:B

3:2 (Before)

Plus 120

4:6 (After)

4-3=1

6-2=4

1+4=5

120/5=24

24*3= 72

There are 72 white marbles at frist.

Thank you.

Post
by **Brenda10** » Fri Oct 22, 2010 4:39 pm

ck123 wrote:Hi anyone

Please help with the following questions:

1) Zara had 70 more dresses than skirts. She sold 3/4 of the dresses and 3/5 of the skirts. She sold 126 more dresses than skirts. What fraction of the remaining clothes that Zara had were skirts?Thanks a lot...

[/img][/list]

Hi, you may refer the following link for solution.

http://www.kiasuparents.com/kiasu/forum ... start=2880

Post
by **iFruit** » Fri Oct 22, 2010 10:58 pm

ck123 wrote:Hi anyone

Please help with the following questions:

2) A seamstress had some white and some black buttons. 60% of the buttons were white. He bought another 120 buttons. Now, the percentage of white buttons became only 40% of the total. How many white buttons did he have at first?

Thanks a lot...

[/img][/list]

I think this is question is incomplete. There can be many solutions as it is.

- greenfinger
- KiasuNewbie
**Posts:**4**Joined:**Fri Apr 08,

Post
by **greenfinger** » Fri Apr 08, 2011 11:27 pm

Hi ,anyone can help me, pls

question:

A wheel made 72 revolutions.It has a radius of 23 cm.How far did it travel?

question:

A wheel made 72 revolutions.It has a radius of 23 cm.How far did it travel?

Post
by **jieheng** » Fri Apr 08, 2011 11:53 pm

greenfinger wrote:Hi ,anyone can help me, pls

question:

A wheel made 72 revolutions.It has a radius of 23 cm.How far did it travel?

The distance it travelled = No. of revolutions * Circumference = No. of revolutions * Pi * Diameter = 72 * 3.14 * ( 2 * 23 ) =

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