Tutor MathsGuru: Ask me for your burning Maths questions!

[tianzhu]

Dharma:

b) Area = 2[ (24 x 3) + (24 x 2) + (3 x 2) ]cm2 = 252cm2

Hi Dharma

If you consider cutting out a big block of 44*36*24 to get 594 smaller cubes of 4cm, you’ll end up with an L shaped remainder.

Depending on how the cuts are done, you can have an L shaped remainder or a remainders of two rectangular blocks.

Best wishes

[Dharma]

tianzhu:

Dharma:

b) Area = 2[ (24 x 3) + (24 x 2) + (3 x 2) ]cm2 = 252cm2

Hi Dharma

If you consider cutting out a big block of 44*36*24 to get 594 smaller cubes of 4cm, you’ll end up with an L shaped remainder.

Depending on how the cuts are done, you can have an L shaped remainder or a remainders of two rectangular blocks.

Best wishes

Don't understand Tianzhu. If block of 44cm x 36cm x 24cm is cut into 4cm
cubes, there will not be anything remainder çause we get 594 nos of 4cm cubes.

Kindly explain. Thanks

[tianzhu]

Dharma:

Don't understand Tianzhu. If block of 44cm x 36cm x 24cm is cut into 4cm

cubes, there will not be anything remainder çause we get 594 nos of 4cm cubes.

Hi Dharma

I mean the remainder from the original block (47 cm long, 38 cm wide, and 24 cm high) after cutting away 44*36*24.

Best wishes

[Dharma]

tianzhu:

Dharma:

Don't understand Tianzhu. If block of 44cm x 36cm x 24cm is cut into 4cm

cubes, there will not be anything remainder çause we get 594 nos of 4cm cubes.

Hi Dharma

I mean the remainder from the original block (47 cm long, 38 cm wide, and 24 cm high) after cutting away 44*36*24.

Best wishes

Thanks Tianzhu. I see it now

[tiger262]

Dharma:

Almighty:

[quote=\"Almighty\"]Hi all,

The question :
A rectangular block of wood, 47 cm long, 38 cm wide, and 24 cm high , was cut into equal cubes of edge 4 cm.
a) What was the maximum number of 4cm cubes which I could cut?
b) What was the total surface area of the remaining piece of wood?

a) my answer : 594 cubes
b) Book answer : 256cm2. My answer is different.Can anyone halp on
section(B)
Thankyou in advance..

Hi Dharma Sir,
This question of mine is unanswered/Can u help me with sec (B)?
Thankyou

b) Area = 2[ (24 x 3) + (24 x 2) + (3 x 2) ]cm2 = 252cm2
(This is based on a remainder block of 24cm x 3cm x 2cm) - if u cut of 44cm from 47cm beginning from the one end.

But if if cut off 44cm from the centre portion of the 47cm length you may get different areas of the remaining shape depending how you make the next along the width.[/quote]Hi Dharma,

If we cut 44 cm from 47 cm beginning from one end, we will be left with an L-shaped block consisting of:

(a) Lengthwise, the 3 cm left out from 47 cm (after using up 44 cm)
(b) Breadthwise, the 2 cm left out from 38 cm (after using up 36 cm)
(c) Heightwise, the full 24 cm tall

Am I correct in my analysis? If I am correct, I cannot understand how its surface area can be as small as 252 sq cm.

Kindly explain your answer in more detail and point out where I am wrong.


Hi Tianzhu,

You have a great mastery in producing marvellous pictures and drawings. I will be most grateful if you can post the drawing of the L-shaped block that I have referred above. Your drawing will illustrate the dimensions of the remainder-block much more lucidly for all to understand. Please try if you can spare time.


Thanks to both you and Dharma.

[Dharma]

tiger262:

Dharma:

[quote=\"Almighty\"]
Hi Dharma Sir,
This question of mine is unanswered/Can u help me with sec (B)?
Thankyou

b) Area = 2[ (24 x 3) + (24 x 2) + (3 x 2) ]cm2 = 252cm2
(This is based on a remainder block of 24cm x 3cm x 2cm) - if u cut of 44cm from 47cm beginning from the one end.

But if if cut off 44cm from the centre portion of the 47cm length you may get different areas of the remaining shape depending how you make the next along the width.

Hi Dharma,

If we cut 44 cm from 47 cm beginning from one end, we will be left with an L-shaped block consisting of:

(a) Lengthwise, the 3 cm left out from 47 cm (after using up 44 cm)
(b) Breadthwise, the 2 cm left out from 38 cm (after using up 36 cm)
(c) Heightwise, the full 24 cm tall

Am I correct in my analysis? If I am correct, I cannot understand how its surface area can be as small as 252 sq cm.

Kindly explain your answer in more detail and point out where I am wrong.

Thanks to both you and Dharma.[/quote]Hi tiger262,

You are right. The area should be the area of the L-shaped block.

[tianzhu]

Hi


Hope this helps.
The drawing is not drawn to scale.

Best wishes
http://farm5.static.flickr.com/4116/4944993552_7c6bcaebd8_z.jpg\">

[tiger262]

tianzhu:

Hi


Hope this helps.
The drawing is not drawn to scale.

Best wishes

Hi Tianzhu,

Thank you very much for the brilliant drawing with superb clarity. You are truly a wizard when it comes to drawings, models and pictures.

Thanks and Regards.

[Almighty]

Almighty:

Almighty:

Hi all,

The question :
A rectangular block of wood, 47 cm long, 38 cm wide, and 24 cm high , was cut into equal cubes of edge 4 cm.
a) What was the maximum number of 4cm cubes which I could cut?
b) What was the total surface area of the remaining piece of wood?

a) my answer : 594 cubes
b) Book answer : 256cm2. My answer is different.Can anyone halp on
section(B)
Thankyou in advance..

Hi Dharma Sir,
This question of mine is unanswered/Can u help me with sec (B)?
Thankyou

Thankyou everyone who spent time to clarify my doubt.Will go through them.

[maths6a]

acehkr3009:

Hi all,


Here is a Before & After question that I come across on one assessment....

Yesterday, Peter has 689 Singapore and Malaysia stamps. This morning, he used 2/5 of his Singapore stamps to exchange for 31 Malaysia stamps. As a result, he now has equal number of Singapore and Malaysia stamps. How many Malaysia does he has yesterday?

Can someone used Model and algebra to solve this question.

Appreciate with Thanks.

Since no one has helped with this one, let me try.

Since 2/5 of S'pore stamps used, there will be 3/5 of S'pore stamps left.
Since Sing = Malaysian after 31 Malaysian added, we start with 3 units for Sing and Malaysian.
S ---- 3 units + 2 units = 5 units at first
M ---- 3 units - 31 at first
5 units + 3 unit - 31 = 689
8 units = 689 + 31
8 units = 720
1 unit = 90
3 units - 31 = 3 x 90 - 31 = 239
Let me know if you still need the model method.