Q&A - P5 Math

[wintay]

Gemini11:

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?

Hi wintay here's another method, using elimination presented in a way which i think kids at P5 should be able to understand :evil:

1) Given, 6 hats and 5 belts= $150 ( mutiple all by 5)
we get... 30 belts and 25 belts= $750

2) Given also, 5 hats and 6 belts= $147 ( mutiple all by 6)
we get... 30 hats and 36 belts = $882

3) since now we know...

30 hats and 36 belts = $882
30 belts and 25 belts= $750

36- 25 belts is obviously = $882-$720
so 11 belts = $132
1 belt=$12

--------------------------------------------------

Hope it helps

Gemini11 :evil:

Hi Gemini,
Thanks!!!

[tianzhu]

Hi


I'll take Q2 first because I miss my ah ma.

Best wishes.

http://farm8.staticflickr.com/7210/6837707220_51b42ebf08_z.jpg\">

[tianzhu]

chokos:

Qn3)
Mark's current age is 1/4 of Ronald's. In 24 years' time, Ronald age will be 14 years less than twice Mark's age. What is Ronald age now?
Model Answer: 20

Hi

Now
Mark’s age ------ 1 unit
Ronald’s age ------ 4 units

In 24 years’ time
Mark’s age ------ 1 unit + 24
Ronald’s age ------ 4 units + 24

Ronald age will be 14 years less than twice Mark's age.

You may use MD or work using units depending on your preference.

1 unit + 24 + 1 unit + 24 ------ 4 units + 24 + 14
1 unit ----- 5

4*5 ------ 20

Ronald is 20 years old now.

Best wishes

[tianzhu]

chokos:

Qn 1)
There are some crystal and glass marbles in a pouch. If 3 crystal marbles are removed from the pouch, the number of crystal marbles left will be 1/6 of the glass marbles left. If 5 glass marbles are removed from the pouch, the number of crystal marbles left will be 1/4 of the glass marbles left. How many marbles are there in the pouch at first?
Model Answer: 62.5

Hi

Based on the question as worded, the answer is 62.5.

At first
Crystal marbles ----- 1 unit + 3
Glass marbles ------ 6 units

In the end
Crystal marbles ----- 1 part
Glass marbles ------ 4 parts

Again, equalise the parts or cross multiply.

(1 unit + 3)*4 ------- 6units - 5
4 units + 12 ------- 6 units – 5

2 units ------ 17
1 unit ------ 8.5

Crystal marbles ------- 11.5
Glass marbles ------- 51
Total number of marbles -------- 62.5

Best wishes

[tianzhu]

zico:

Is there a algerbra way to solve this?

Hi

Yes, there is.

Best wishes

[2snoopy]

Is primary 5 students start to learn algebraic equation in school? If yes, then can use my method.

[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