Q&A - P5 Math

[PiggyLalala]

tianzhu:

PiggyLalala:

:thankyou: for the solution.
Q28 is really a tough one. I was about to use similar triangles ( which is not in the primary school syllabus) to find the area.

Questions on area can be quite tough. Any techniques/advice/steps for the pupils to think through when solving challenging area questions? Thanks

Hi

First, you must have faith in the KS philosophy.

Keep in Syllabus.
Keep it Simple
Keep it Short.

Rearrange the areas into familiar looking shapes; look nothing more than what your teacher taught you in school.

Best wishes

Thank you for your advice again.
I have no wish to coach my child additional concept too as I strongly believe that all the questions tested in the primary school exam and PSLE can be done solely based on the primary school syllabus.

Got your hints. Keep the solution simple and short. Do not teach extra.
and most importantly try to rearrange the areas into familiar looking shapes; look nothing more than what your teacher taught you in school.

:thankyou:

[tianzhu]

PiggyLalala:

:thankyou:

Hi

You're welcome.

Best wishes

[pixiedust]

Thank you, tianzhu ! I looked at q28 all day then I told me ds I have to ask my internet friends !


I really 心服口服 with your elegant solutions! Q17, yes I can digest, no need slides. Thanks again!

[tianzhu]

pixiedust:

Thank you, tianzhu ! I looked at q28 all day then I told me ds I have to ask my internet friends !


I really 心服口服 with your elegant solutions! Q17, yes I can digest, no need slides. Thanks again!

Hi

You're welcome.

For Q17, I've reduced 80:140 to the lowest equivalent ratios of 4:7 to make the calculations easier.Please refer to the revised solution in earlier post.The rest remains the same.

Best wishes

[bbkoala]

Hi


I have a Maths question that has been bothering me for weeks!
Hope someone can enlighten me…

100 workers were paid a total of $24750. If 25% of them received 20% more money than the remaining men, calculate the amount received by each man from the group who got less.

Ans is $150.

I can’t get this value, and tried working backwards using $150, but couldn’t get $24750.

Many thanks!

[tianzhu]

bbkoala:

100 workers were paid a total of $24750. If 25% of them received 20% more money than the remaining men, calculate the amount received by each man from the group who got less.

Ans is $150.

I can't get this value, and tried working backwards using $150, but couldn't get $24750.

Hi

25% ----- 25 workers
75% ------ 75 workers

The lower wage worker receives 1 unit each

75 units + 90 units (20% more) ------- 24750
165 units ----- 24650

1 unit ----- 150

Best wishes

[ozora]

need guide in these 2 questions

q1. http://i54.tinypic.com/119xzpv.jpg\">
q2. Apple and Berth had a total of $300 to spend.
Apple spent thrice of the amount she has left while Berth spent twice of the amount she has left. Given that the 2 total friends had a total of $90 left, how much did they have at first?

[ksme]

ozora:

need guide in these 2 questions

q1. http://i54.tinypic.com/119xzpv.jpg\">
q2. Apple and Berth had a total of $300 to spend.
Apple spent thrice of the amount she has left while Berth spent twice of the amount she has left. Given that the 2 total friends had a total of $90 left, how much did they have at first?

Is the answer for question 1 : 184?

Total area of non-shaded region = 240+56 = 296.
Therefore, area of shaded region = 480-296 = 184.

The error in your calculation is because of double counting 56 since area of 1 of the big triangle which is half of the rectangle is already inclusive of 1 of the 56.

Hope this is clear.

[ksme]

ozora:

need guide in these 2 questions


q2. Apple and Berth had a total of $300 to spend.
Apple spent thrice of the amount she has left while Berth spent twice of the amount she has left. Given that the 2 total friends had a total of $90 left, how much did they have at first?

Ozora,
Here's my working:
Let A be 1 unit of Apple's amount.
Let B be 1 unit of Berth's amount.

At the beginning : 4A + 3B = $300 ......(1)

At the end : A + B = S$90
=> 3A + 3B = $90 x 3 = $270..... (2)

Comparing (1) and (2) => A = $30

Since Apple has 4units at first, she will have $30 x 4 = $120

Total at first is $300. Therefore, Berth's share at first is $180.

My workings is not very elegant. Maybe others have a more elegant way to work this out.

Hope this helps.

[bbkoala]

Hi tianzhu


Thanks for your fast response.

Haha...to think that I finally understood the question after looking at your answer!

Lucky my gal asked me to post on KSP if I can't figure out the answer