Q&A - P3 Math
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lee_yl:
Of course I can.
I am not sure if you have properly understood the question. This is not about picking the balls one at a time but rather, as a group of \"n\" balls. What is the minimum value of n such that there will be 3 balls of the same colour among the balls. As reasoned earlier, n cannot be 7 or 8, and 9 should be the correct answer. You can draw to analyse the question but probably not the manner you suggested.pirate:
Well... the answer would be 7 if there were 4 balls of each colour instead of 3.
RBG
RBG
RBG
RBG
Actually, it becomes ridiculously easy once you draw it out. Which leads me to question whether this kind of question actually tests a student's understanding and grasp of concept or simply whether the student had been exposed to something like that before.
So, more tuition?
Only if there were 4 balls of each colour would the answer be 7.
RBG
RBG
RBG
RBG
If there were 3 balls of each colour (as per the question), the answer would be 9.
RBGY
RBGY
RBGY
But if you want a group that will always have at least 3 balls of different colours, then it would 7.
RBGY
RBGY
RBGY
Unless there were 4 balls of each colour, then the answer will be back to 9 if you want a group which will always have 3 different colours.
RBG
RBG
RBG
RBG
But if you have a bag of 15 balls containing 3 balls of each colour, the answer would be 11.
RBGYP
RBGYP
RBGYP
And if you have a bag of a gazillion balls still containing dunno-how-many-equal-number of balls of 5 colours, the answer would still be 11 if you want a group that will always contain at least 3 balls of the same colour.
RBGYP
RBGYP
RBGYP
RBGYP
RBGYP
....
....
....
But if you want a group containing exactly 3 balls of the same colour, then it won't work and you can't if you have a gazillion balls.
Model drawing is fun! After all, this is still P3 maths. -
ageBunny27
 Post subject: P3 Maths
Posted:Â 24 Apr 2015 18:41Â
OrangeBelt
Joined:Â 26 Jan 2011 21:18
Posts:Â 71Â
Hi,Â
I need help on this question. Can someone help as I need to explain to my gal?Â
1. Ali has a total of $76. Some are $2 notes and the rest are $5 notes. He has 4 more $5 notes than $2 notes. How many $2 notes and $5 notes does Ali have?Â
Thank you! -
Bunny27:
ageBunny27
 Post subject: P3 Maths
Posted:Â 24 Apr 2015 18:41Â
OrangeBelt
Joined:Â 26 Jan 2011 21:18
Posts:Â 71Â
Hi,Â
I need help on this question. Can someone help as I need to explain to my gal?Â
1. Ali has a total of $76. Some are $2 notes and the rest are $5 notes. He has 4 more $5 notes than $2 notes. How many $2 notes and $5 notes does Ali have?Â
Thank you!
Model diagram:
$2 ( u )
$5 ( u ) (4)
2(u) + 5(u+4) -> 76
2u+5u+20-> 76
7u -> 56
u -> 8
$2 notes -> 8
$5 notes -> 8+4 = 12 -
Bunny27:
ageBunny27
 Post subject: P3 Maths
Posted:Â 24 Apr 2015 18:41Â
OrangeBelt
Joined:Â 26 Jan 2011 21:18
Posts:Â 71Â
Hi,Â
I need help on this question. Can someone help as I need to explain to my gal?Â
1. Ali has a total of $76. Some are $2 notes and the rest are $5 notes. He has 4 more $5 notes than $2 notes. How many $2 notes and $5 notes does Ali have?Â
Thank you!
Hmm, not sure if it can be done this way. But I will do this question the following way..
76 - 20 = $56 ...... Since already known 4 notes are $5 bill
Then,
Each set = $2 + $5 = $7
No of sets = 56 / 7 = 8
Therefore, there are 8 $2 bill and 12 $5 bill. -
Thanks all for the help! Will draw out the models and explain to my gal.
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nicnac:
Thanks all for the help! Will draw out the models and explain to my gal.Bunny27:
ageBunny27
 Post subject: P3 Maths
Posted:Â 24 Apr 2015 18:41Â
OrangeBelt
Joined:Â 26 Jan 2011 21:18
Posts:Â 71Â
Hi,Â
I need help on this question. Can someone help as I need to explain to my gal?Â
1. Ali has a total of $76. Some are $2 notes and the rest are $5 notes. He has 4 more $5 notes than $2 notes. How many $2 notes and $5 notes does Ali have?Â
Thank you!
Hmm, not sure if it can be done this way. But I will do this question the following way..
76 - 20 = $56 ...... Since already known 4 notes are $5 bill
Then,
Each set = $2 + $5 = $7
No of sets = 56 / 7 = 8
Therefore, there are 8 $2 bill and 12 $5 bill. -
hi hi, I need some help on this question.
Mr Wong has some marbles. If he gives 6 marbles to each of his children, he will be left with 3 marbles. If he gives 8 marbles to each of his children, he will need 5 more marbles.
a) how many children does Mr Wong have?
b) how many marbles does Mr Wong have?
How to solve this question short of using algebra? Thanks! -
fav_giraffe:
I donch think this is p3....maybe p4 gephi hi, I need some help on this question.
Mr Wong has some marbles. If he gives 6 marbles to each of his children, he will be left with 3 marbles. If he gives 8 marbles to each of his children, he will need 5 more marbles.
a) how many children does Mr Wong have?
b) how many marbles does Mr Wong have?
How to solve this question short of using algebra? Thanks! -
No leh, my son p3 school maths hw
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fav_giraffe:
No leh, my son p3 school maths hw
Perhaps I remember wrongly.
Additional from 6 to 8 (each) = 2
Total additional needed = 3 + 5 = 8
Therefore no. of children = 8/2 = 4
Total marbles = (6 * 4) + 3 = 27
**check : if give 8, needed 32, ie, 5 short. QED. -
fav_giraffe:
http://i58.tinypic.com/jb06it.jpg\">hi hi, I need some help on this question.
Mr Wong has some marbles. If he gives 6 marbles to each of his children, he will be left with 3 marbles. If he gives 8 marbles to each of his children, he will need 5 more marbles.
a) how many children does Mr Wong have?
b) how many marbles does Mr Wong have?
How to solve this question short of using algebra? Thanks! -
fav_giraffe:
Another approach:hi hi, I need some help on this question.
Mr Wong has some marbles. If he gives 6 marbles to each of his children, he will be left with 3 marbles. If he gives 8 marbles to each of his children, he will need 5 more marbles.
a) how many children does Mr Wong have?
b) how many marbles does Mr Wong have?
How to solve this question short of using algebra? Thanks!
http://i60.tinypic.com/2moz88j.jpg\"> -
thank u! let me try to teach my son this.
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fav_giraffe:
A similar question came out in my DD's P3 test and most of the class can't do it. Popular question to differentiate the better students.hi hi, I need some help on this question.
Mr Wong has some marbles. If he gives 6 marbles to each of his children, he will be left with 3 marbles. If he gives 8 marbles to each of his children, he will need 5 more marbles.
a) how many children does Mr Wong have?
b) how many marbles does Mr Wong have?
How to solve this question short of using algebra? Thanks! -
lee_yl:
More like popular question to differentiate those with tuition and those without. :razz:
A similar question came out in my DD's P3 test and most of the class can't do it. Popular question to differentiate the better students.fav_giraffe:
hi hi, I need some help on this question.
Mr Wong has some marbles. If he gives 6 marbles to each of his children, he will be left with 3 marbles. If he gives 8 marbles to each of his children, he will need 5 more marbles.
a) how many children does Mr Wong have?
b) how many marbles does Mr Wong have?
How to solve this question short of using algebra? Thanks! -
fav_giraffe:
Hi fav_giraffehi hi, I need some help on this question.
Mr Wong has some marbles. If he gives 6 marbles to each of his children, he will be left with 3 marbles. If he gives 8 marbles to each of his children, he will need 5 more marbles.
a) how many children does Mr Wong have?
b) how many marbles does Mr Wong have?
How to solve this question short of using algebra? Thanks!
Good Evening.
Here’s an example for a similar question. Please refer to the slide.
Hope this helps.
Best wishes
http://farm6.staticflickr.com/5346/8787021811_022a432b64_z.jpg\"> -
How does this type of question fit into the official Primary 3 syllabus which is limited to \"solving up to 2-step word problems\"?
I count, count and count and I keep getting more than 2 steps. :scratchhead: -
pirate:
That was why I had the impression that it's not P3.How does this type of question fit into the official Primary 3 syllabus which is limited to \"solving up to 2-step word problems\"?
I count, count and count and I keep getting more than 2 steps. :scratchhead: -
Nebbermind:
Pardon me as I am not very familiar with p3 syllabus but I think guess and check method can solve it immediately. What do you think?
That was why I had the impression that it's not P3.pirate:
How does this type of question fit into the official Primary 3 syllabus which is limited to \"solving up to 2-step word problems\"?
I count, count and count and I keep getting more than 2 steps. :scratchhead: -
Nebbermind:
Funny, i see a similar question posed in the P5 thread. So is this a P3 qn or P5 qn?
That was why I had the impression that it's not P3.pirate:
How does this type of question fit into the official Primary 3 syllabus which is limited to \"solving up to 2-step word problems\"?
I count, count and count and I keep getting more than 2 steps. :scratchhead:
http://www.kiasuparents.com/kiasu/forum/viewtopic.php?f=68&t=25129&start=6330