Q&A - P3 Math

[tianzhu]

Hi

Hope this helps

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[Tranquility8706]

Thank you very much… Tianzhu

[john.09525316]

[quote]how did you get 142?[/quote]
Sorry I have made a silly and careless mistake.
It should be 70.

[owlparents]

Hi,


I have this Maths problem from Pei Chun P3 SA2 2008. Pls help. Thanks.

Grandpa has some stamps. If he gives 6 stamps to each of his grandchildren, he will have 5 stamps left over. If he gives 8 stamps to each of his grandchildren, he will be hsort of 9 stamps.

a) How many grandchildren does Grandpa have?

b) How many stamps does Grandpa have?

[radiantmum]

I can’t sleep so keeping myself occupied solving maths problem.


Owlparents, (a) 7 & (b) 47

6x+5 = 8x - 9
14 = 2x
7 = x

Oh but wait a minute - does P3 knows algebra?

[owlparents]

Thanks RadiantMum! Your answers are correct. But no algebra for P3.


Any other methods? Thanks.

[radiantmum]

Hi owlparents,


sorry it took a little while as I have no idea what P3's current methods are (now you know i belong to the old algebra generation :oops: ). I was
referring to page 1 of this thread based on Lizawa's method ...

multiple of 6s: 6, 12, 18, 24,30,36, 42
(+5 since extra 5 stamps) : 11,17,23,29,25, 41, 47

multiple of 8s: 8, 16, 24, 32, 40, 48, 56
(-9 since short of 9 stamps) : -1, 7, 15, 23, 31, 39, 47

So 47 is the matching answer and if you count by blocks, it's 7 !

Geez, why cant they teach algebra if they want to make maths so difficult for P3 :shock:

[Tang]

owlparents:

Hi,


I have this Maths problem from Pei Chun P3 SA2 2008. Pls help. Thanks.

Grandpa has some stamps. If he gives 6 stamps to each of his grandchildren, he will have 5 stamps left over. If he gives 8 stamps to each of his grandchildren, he will be hsort of 9 stamps.

a) How many grandchildren does Grandpa have?

b) How many stamps does Grandpa have?

Instead of 6 stamps, each grandchild is given 8 stamps, so each gets 2 more stamps.

With 5 stamps left over in addition to 9 stamps short, total stamps given out to the grandchildren is 5 + 9 = 14 stamps.

Since each grandchild receives 2 more stamps and 14 stamps are given out, number of grandchildren is 14 divided by 2, that is 7 grandchildren.

Number of stamps = 6 x 7 + 5 = 47 stamps.

[owlparents]

Thanks a lot for your help. Will try to digest this first and then think of how to explain to my girl.

[acforfamily]

owlparents:

Hi,


I have this Maths problem from Pei Chun P3 SA2 2008. Pls help. Thanks.

Grandpa has some stamps. If he gives 6 stamps to each of his grandchildren, he will have 5 stamps left over. If he gives 8 stamps to each of his grandchildren, he will be hsort of 9 stamps.

a) How many grandchildren does Grandpa have?

b) How many stamps does Grandpa have?

Another way to look at this solution is looking at the difference between the 2 ways.

For each child, the difference in the 2 ways is (8-6) i.e. 2 stamps.
In total, the difference in the 2 ways is (9+5) i.e. 14 stamps
Therefore, the number of children to have a difference of 14 stamps is (14 / 2) i.e. 7 children.

Hope this helps.