Q&A - P5 Math

[chokos]

Hi all,

Thanks for helping.
I need help to solve the following questions:

Q 1) Some pupils from 5K, 5L and 5M took part in a Social Studies quiz. 34 participants were from 5L and 5M. 21 participants were not from 5L and 19 participants were not from 5M. How many pupils from these 3 classes took part in the quiz? Model Answer: 37pupils

Q 2) Mrs Lee spent ½ of her money on some almond cookies and 2/5 of the remaining money on 6 slices of butter cake. Each slice of butter cake costs thrice as much as one almond cookie. How many almond cookies did she buy? Model Answer: 18 almond cookies.

Q3) Three sisters Lisa, Ming and Nora shared the cost of a present for their father. Lisa paid ¼ of the total share of Ming and Nora. Ming paid 1/9 of the total share of Lisa and Nora. Nora paid $60 more than Ming. How much did the present cost? Model Answer: $100

Q4) Jason and Kevin were given some money each. If Jason and Kevin spent $100 and $50 each day respectively. Jason would have $1300 when Kevin had spent all his money. If Jason and Kevin spent $50 and $100 each day respectively, Jason would have $3700 when Kevin had spent all his money. How much money was given to Jason at the beginning.
Model Answer: $4500

[small]

wintay:

Can anyone help to solve the problem sum below. Thanks


6 hats and 5 belts cost $150. 5 hats and 6 belts cost $147. What is the cost of one belt?

Another way to solve this question.

Given that:
6 hats and 5 belts cost $150
5 hats and 6 belts cost $147

add togother become:
11 hats and 11 belts cost $297

divide by 11
1 hat and 1 belt cost $27

x 5
5 hats and 5 belts cost $135

Given that:
5 hats and 6 belts cost $147

1 belt ---- $147 - $135 = $12

[KSgal]

chokos:

Hi all,

Thanks for helping.
I need help to solve the following questions:

Q 1) Some pupils from 5K, 5L and 5M took part in a Social Studies quiz. 34 participants were from 5L and 5M. 21 participants were not from 5L and 19 participants were not from 5M. How many pupils from these 3 classes took part in the quiz? Model Answer: 37pupils

5L + 5M: 34

21 not from 5L means that the 21 are from 5K + 5M

19 not from 5M means that the 19 are from 5K + 5L

Notice that if you add all the numbers up, you will get 2 5K, 2 5L and 2 5M.

So:

2 5K, 2 5L, 2 5M--34+21+19=74
No. of pupils from all 3 classes (1 5K, 1 5L, 1 5M)--74/2=37

Ans: 37 pupils

Hope this helps ^_^

[KSgal]

chokos:

Q 2) Mrs Lee spent ½ of her money on some almond cookies and 2/5 of the remaining money on 6 slices of butter cake. Each slice of butter cake costs thrice as much as one almond cookie. How many almond cookies did she buy? Model Answer: 18 almond cookies.

Actually, I've got 45 for this question. Not too sure if I am correct. Here's my working:

Spent on butter cake--2/5 X 1/2(remainder) = 1/5 of total
1/5 of total worth of almond cookies--6 X 3 = 18

However, 1/2 was spent on almond cookies, not 1/5.

1/2=5/10 of total
1/5=2/10 of total

2/10--18 cookies
1/10--18/2=9 cookies
5/10--9 X 5= 45 cookies

My answer: 45 cookies

[KSgal]

chokos:

Q3) Three sisters Lisa, Ming and Nora shared the cost of a present for their father. Lisa paid ¼ of the total share of Ming and Nora. Ming paid 1/9 of the total share of Lisa and Nora. Nora paid $60 more than Ming. How much did the present cost? Model Answer: $100

1st ratio:
L: 1u x2 = 2u
M+N: 4u x2= 8u
Total: 5u x2= 10u

2nd ratio:
M: 1u
L+N: 9u
Total: 10u


Since the price of the present will not change, the total of both ratio should be the same. Thus, we x2 the total of the 1st ratio to make the total of both ratios to be the same. And since we x2 the total, we need to x2 everything else in the 1st ratio.

No. of units for Nora--9u(L+N) - 2u(L) = 7u(N)
Diff between Nora and Ming--7u-1u=6u
6u--$60
1u--$60/6=$10
10u--$10 X 10= $100

Ans: $100

[buds]

Helloooo again, tianzhu! :peekaboo:


I have a few more for you here.

I am thinking of a fraction.
The sum of its numerator and denominator is 20.
When i add 22 to its denominator, the fraction becomes 1/6.
What is the fraction i am thinking of?

This question carries 4 marks! :yikes:

Benjamin left Singapore for an 8-day exchange programme in Perth.
When he returned, he realized he had to tear off 8 pages from his day to day calendar.
The sum of all the dates on the pages he tore is 84.
On which day did he leave Singapore?

1. 5 February
2. 6 January
3. 7 June
4. 8 August

This wan 2 marks.

I suppose the task at hand is more to the issue of solving such questions
without having to spend too much time on them. When have to
think too long & too much over a few questions my DD1 gets her
usual what she calls mental block.. head jammed.. cannot think.. :slapshead:

[Gemini11]

buds:

I am thinking of a fraction.

The sum of its numerator and denominator is 20.
When i add 22 to its denominator, the fraction becomes 1/6.
What is the fraction i am thinking of?

Since the Final Fraction can become 1/6, which means the numerator must be able to be divided by 6.

From 1-20, only 6 and 12 can be divided by 6.

So we try 6 first.

Given, he sum of its numerator and denominator is 20.

if numerator = 6, demominator will be 14

Given, When i add 22 to its denominator, the fraction becomes 1/6

Check, 6/ ( 14 +22) = 6/36 = 1/6 ( correct!)

What is the fraction i am thinking of?

Answer: 6/14

buds:

Benjamin left Singapore for an 8-day exchange programme in Perth.
When he returned, he realized he had to tear off 8 pages from his day to day calendar.
The sum of all the dates on the pages he tore is 84.
On which day did he leave Singapore?

1. 5 February
2. 6 January
3. 7 June
4. 8 August

For this question, unless you use the AP, GP formula ( which will not be taught till JC1), the only way to solve it will be by trial and error ( correct me if i'm wrong )

The answer is 7 june ( which happened to be my bday. ok that's totally random) well, let's check...

7 + 8 + 9 + 10 + 11 + 12 + 13 +14 = 84 ( correct !)

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Hope it helps

Gemini11 :evil:
PS: Sorry tianzhu hope you dont mind i hijacked your questions

[tianzhu]

Gemini11:

Gemini11 :evil: [/b]
PS: Sorry tianzhu hope you dont mind i hijacked your questions

Hi Gemini11

Thank you for helping to solve questions in KSP.

Please do not treat it as “hijack of questions”.

I see it as parents and students having an alternative source of getting their problems solved.

The long term growth and sustainability of a forum depend much on the willingness of members to come forward and share. The entry of new and enthusiastic members like you can only add vibrancy and dynamism and at the same time introduce new perspectives of looking at a question.

Best wishes

[Gemini11]

tianzhu:

Gemini11:

Gemini11 :evil: [/b]
PS: Sorry tianzhu hope you dont mind i hijacked your questions

Hi Gemini11

Thank you for helping to solve questions in KSP.

Please do not treat it as “hijack of questions”.

I see it as parents and students having an alternative source of getting their problems solved.

The long term growth and sustainability of a forum depend much on the willingness of members to come forward and share. The entry of new and enthusiastic members like you can only add vibrancy and dynamism and at the same time introduce new perspectives of looking at a question.

Best wishes

Tianzhu, Thanks for that

Nothing great just trying to help out with some questions when I'm free at home

[joyjoyleong]

I'm new here n i'm looking for private tutor to teach English to my Pri 5 kid. Pls recommend< thanks!