Q&A - PSLE Math

[meimeitan]

Hi! All,


Can solve the following question?

June Jie bought some candies that came in square pyramid packages. Each pyramid had a square base area of 1 cm square and a vertical height of 1 cm. He then packed the candies in a box measuring 6 cm by 4 cm by 4 cm. What was the maximum number of such candies he could pack into the box?

thanks.

[atutor2001]

meimeitan:

Hi! All,


Can solve the following question?

June Jie bought some candies that came in square pyramid packages. Each pyramid had a square base area of 1 cm square and a vertical height of 1 cm. He then packed the candies in a box measuring 6 cm by 4 cm by 4 cm. What was the maximum number of such candies he could pack into the box?

thanks.

The first layer can have 6 x 4 = 24 pyramids.

Turn the pyramids upside down (invert) to sit in the first layer, we get 5 x 3 = 15 pyramids

That means for every 1 cm height of the box, we can pack 24 + 15 = 39 pyramids.

Total height of 4cm can pack 39 x 4 = 156 (is it correct?)

Below is my best attempt of presenting the picture for stacking of 5 pyramids (looking from the top) - 4 upright pyramids and 1 inverted in the centre. The pattern can be repeated for each layer for 6cm x 4cm.
_______
| .._|_....|
|_|_|_|_.|
| .|_|_|...|
|__.|__..|

[meimeitan]

Hi!


thanks for your prompt reply. The answer given is 176 and the word maximum is underlined and bloded to remind students that the answer should be miximum. Any idea?

thanks :lol:

[atutor2001]

meimeitan:

Hi!


thanks for your prompt reply. The answer given is 176 and the word maximum is underlined and bloded to remind students that the answer should be miximum. Any idea?

thanks :lol:

Sorry lah. I think high think low, think left, think right, still can't put in the extra 20 pyramids. Hopefully one of the experts here will post the correct method soon.

[Brenda10]

Hi all, need your help on the following question.



Rosyth 2010 CA1 P2 Q16 (given answer Fazillah:39, Linda: 35)

Fazillah, Linda and Winnie each owned a collection of comics. The total collection owned by Linda and Winnie was 3/2 as many comics as Fazillah owned. Linda owned 4/5 as many comics as the total collection owned by Fazillah and Winnie. If Winnie owned 169 fewer comis than Linda, how many comics must Fazillah and Linda each give to Winnie in order for the three girls to have the same number of comics ?

Thank you

[Vanilla Cake]

Brenda10:

Hi all, need your help on the following question.

Rosyth 2010 CA1 P2 Q16 (given answer Fazillah:39, Linda: 35)

Dear Brenda10,
Checked with my younger sister's papers for this school and the given answers are correct ie Fazillah: 39 and Linda: 65

Brenda10:

Fazillah, Linda and Winnie each owned a collection of comics. The total collection owned by Linda and Winnie was 3/2 as many comics as Fazillah owned. Linda owned 4/5 as many comics as the total collection owned by Fazillah and Winnie. If Winnie owned 169 fewer comis than Linda, how many comics must Fazillah and Linda each give to Winnie in order for the three girls to have the same number of comics ?

My younger sister's workings
L+W : F
3 : 2
27 : 18

L : F+W
4 : 5
20 : 25

F: 18u
L: 20u
W: 7u

13u=169

(18u+20u+7u)/3=15u
18u-15u=3u
3u=39 (F)
20u-15u=5u
5u=65 (L)

Fazillah and Linda must gave up 39 comics and 65 comics respectively to Winnie in order for the three girls to have the same number of comics.

Off topic, you had mentioned in another thread that you had bought some science assessment books for your DD to read and understand how these answers are worded. If you don't mind, pls share the title of these books.Also thks for your reply for the 2 questions on P6 English in another thread.

[Vanilla Cake]

Dear Brenda10,


Sorry to bother you. Could you pls visit P6 Nanyang Maths CA1 2010 Paper 1 Q11 [2 marks]. It's on tessallation.
The answer given is option (2) which is 2 unit shapes have been tessellated wrongly. But my younger sister (P5) thinks it should be option (4) ie 4 unit shapes have been tessellated wrongly.

Pls help to solve this question and thanks for your time cum effort.

[Brenda10]

Vanilla Cake:

Brenda10:

Hi all, need your help on the following question.

Rosyth 2010 CA1 P2 Q16 (given answer Fazillah:39, Linda: 35)

Dear Brenda10,
Checked with my younger sister's papers for this school and the given answers are correct ie Fazillah: 39 and Linda: 65

Brenda10:

Fazillah, Linda and Winnie each owned a collection of comics. The total collection owned by Linda and Winnie was 3/2 as many comics as Fazillah owned. Linda owned 4/5 as many comics as the total collection owned by Fazillah and Winnie. If Winnie owned 169 fewer comis than Linda, how many comics must Fazillah and Linda each give to Winnie in order for the three girls to have the same number of comics ?

My younger sister's workings
L+W : F
3 : 2
27 : 18

L : F+W
4 : 5
20 : 25

F: 18u
L: 20u
W: 7u

13u=169

(18u+20u+7u)/3=15u
18u-15u=3u
3u=39 (F)
20u-15u=5u
5u=65 (L)

Fazillah and Linda must gave up 39 comics and 65 comics respectively to Winnie in order for the three girls to have the same number of comics.

Off topic, you had mentioned in another thread that you had bought some science assessment books for your DD to read and understand how these answers are worded. If you don't mind, pls share the title of these books.Also thks for your reply for the 2 questions on P6 English in another thread.

Hi Vanilla Cake

Thank you for your fast respond. I'm happy that dd will take PSLE same year with your sister.

Yes. There was a typing error and the answer key was 65 not 35. Thank you for your highlight.

The two science books that I bought were:

Science 5 & 6 Teacher Circle - JustEducation
Science Process Skills - Teacher@work

Thank you and looking forward to learn more from you. :lol:

[Brenda10]

Vanilla Cake:

Dear Brenda10,


Sorry to bother you. Could you pls visit P6 Nanyang Maths CA1 2010 Paper 1 Q11 [2 marks]. It's on tessallation.
The answer given is option (2) which is 2 unit shapes have been tessellated wrongly. But my younger sister (P5) thinks it should be option (4) ie 4 unit shapes have been tessellated wrongly.

Pls help to solve this question and thanks for your time cum effort.

Hi Vanilla Cake

Don't need to say sorry and I think we have more to learn from you.

Now dd is still in the bed. Will let her try this particular question and see what the answer is and get back to you soon.

Thank you

[Brenda10]

Brenda10:

Vanilla Cake:

Dear Brenda10,


Sorry to bother you. Could you pls visit P6 Nanyang Maths CA1 2010 Paper 1 Q11 [2 marks]. It's on tessallation.
The answer given is option (2) which is 2 unit shapes have been tessellated wrongly. But my younger sister (P5) thinks it should be option (4) ie 4 unit shapes have been tessellated wrongly.

Pls help to solve this question and thanks for your time cum effort.

Hi Vanilla Cake

Don't need to say sorry and I think we have more to learn from you.

Now dd is still in the bed. Will let her try this particular question and see what the answer is and get back to you soon.

Thank you

Hi Vanilla Cake

DD answer is Option 2. She said there was a one in the center shap out and the last one should not leave a gap otherwise it will create problem (soemthing like overlap) when continuous to tessellate.

Thank you