Tutor MathsGuru: Ask me for your burning Maths questions!

[Vanilla Cake]

CJM:

Can u pls advise why need to add another 150 to K ?

Because the kettle received 150 ml of water from the jug.

[Hiroii-kun]

Dear gurus, please help with this qn.


There are 2 bags of stones labeled A & 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 stones in bag A and 75% of stones in bag B are black?

[Vanilla Cake]

Hiroii-kun:

Dear gurus, please help with this qn.


There are 2 bags of stones labeled A & 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 stones in bag A and 75% of stones in bag B are black?

This question is similar to RGPS 2009 P6 SA1 Paper 2 Q18 and pls refer to http://psle2010a.blogspot.com/2010/04/percentage-p6-2009-sa1-p2-rgs-q18_5512.html for reference while waiting for others to post their solutions.

Need to go to school now and sorry that I don't have time to post the solution for this question.The answer is 175 black and 25 white stones should be transferred from bag B to bag A so that 50% of stones in bag A and 75% of stones in bag B are black.

Hope that others like Uncle Dharma will help to check my answers and post the solution.

[Hifive]

Hi kancheongmum


Thanks for your solution.

Can you pls explain how do you work out the height of the shaded triangles?

Thanks!

[Hifive]

Hi everyone


Need help with this question
Source : ACS (Primary) SA2 2009 - P5

In the figure, a rectangular piece of paper is folded at two of its corner X and Z as shown. Find angle XYZ.

http://postimage.org/image/35kpmw8xw/

Thanks in advance.

[Vanilla Cake]

Hifive:

Hi kancheongmum


Thanks for your solution.

Can you pls explain how do you work out the height of the shaded triangles?

Thanks!

Hi Hifive,

While waiting for kancheongmum's reply, pls see whether my explanation helps or not?

(a) Look at the bases of the 2 triangles that are 2m, the total height of them is 24m
(b) Look at the bases of the 2 triangles that are 6m, the total height of them is 12m
(c) Calculate total area of the 2 triangles with bases as 2m-> Total area =1/2x2x24=24m²
(d) Calculate total area of the 2 triangles with bases as 6m-> Total area =1/2x6x12=36m²
(e) Add (24+36)m²= 60m² which is the total shaded area
(f) 2 marks is in your bag.

VC's mum

[Hifive]

Hi VC’s mum


yes, yes, your explanation helps! Thank you so much!

[Vanilla Cake]

Hifive:

Hi everyone


Need help with this question
Source : ACS (Primary) SA2 2009 - P5

In the figure, a rectangular piece of paper is folded at two of its corner X and Z as shown. Find angle XYZ.

http://postimage.org/image/35kpmw8xw/

Thanks in advance.

Hi Hifive,

This question is not easy to explain as DD2 add dotted lines and labeled the angles in the original diagram. As both my daughters are in school, I am not able to scan DD2's solution.

Here's DD2's solution:

(180⁰-60⁰)÷2=60⁰
180⁰-90⁰-60⁰=30⁰
Angle XYZ=180⁰-30⁰-30⁰-20⁰-20⁰ = 80⁰

Pls wait for others to post their solutions as it's not easy to understand without adding dotted lines and labeling the angles in the original diagram.
BTW, Observer had posted his http://psle2010a.blogspot.com/2010/09/angles-p5-2009-sa2-acs-p2-q11.html for your question in his blog.Check it up.

VC's mum

[Hifive]

Hi VC’s mum


Thank you for your explanation and solution! Have a nice day!

[Ngserene617]

Hi can you help me this ques;

1. Zoe and Sean has $20 altogether.
Zoe has $4 more than Sean.
How much money does each of them have?

Thanks

mathsguru:

Original Title: Let MathsGuru Answer Your Burning Maths Questions!

:welcome:

Dear Parents,

Are you frustrated/stuck when helping your child solve his/her Maths questions? Are you inclined to use Algebra most of the time? Do you have difficulty trying to use diagrams or other heuristic methods (that Primary School students learn) to solve?

:idea: Post your questions here and see how MathsGuru solve them to the best of her ability. Detailed solutions will be posted back in this thread.

So start asking and watch this space!!

Cheers :celebrate: ,
MathsGuru

P/S (Disclaimer, in case you're wondering...):
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