Tutor MathsGuru: Ask me for your burning Maths questions!

[super star]

Thank you

Vanilla Cake:

super star:

http://www.postimage.org/image.php?v=TsA0t7J

The figure is madeup of two identical rightangled triangles,a small square & a big square.the perimeter of the shaded region is 50cm,& the total area of the two square is 254.5sqcm.
find the total area of the two shaded right-angled triangle.

This question is from RGPS 2009 P6 SA1 Paper 2 Q14 and pls refer to http://psle2010a.blogspot.com/2010/04/area-p6-2009-sa1-p2-rgs-q14_4890.html.

VC's mum

[atutor2001]

super star:

Thank you

Vanilla Cake:

[quote=\"super star\"]http://www.postimage.org/image.php?v=TsA0t7J

The figure is madeup of two identical rightangled triangles,a small square & a big square.the perimeter of the shaded region is 50cm,& the total area of the two square is 254.5sqcm.
find the total area of the two shaded right-angled triangle.

This question is from RGPS 2009 P6 SA1 Paper 2 Q14 and pls refer to http://psle2010a.blogspot.com/2010/04/area-p6-2009-sa1-p2-rgs-q14_4890.html.

VC's mum

[/quote]Very sad that P6's are made to do such question. The strategy tested is good but the use of an area of 254.5 cm2 is bad. Should have just use a whole number.

[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.

[Herbie]

Hi Dharma


I have one qn, please see below

Mr Tan took 6 hours to drve from Town A to Town B.
Mr Lm who started at the same time as Mr Tan took 4 hours to drive from Town B to Town A

When they met each other, they were 48km away from mid point of Town A and Town B

(a) Calculate the distance between Town A and Town B
(b) Calculate the speed of Mr Tan


Working
Time
Tan : Lim
6: 4


Ratio of Speed/Distance
Tan: Lim
6: 4
2:3

3u- 2u = 1u
Iu = 48km
10u = 48km x 10
=480km

(b)480/6 = 80km/h

Is the working for (a) correct??


Thanks and regards,

[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

[Dharma]

Herbie:

Hi Dharma


I have one qn, please see below

Mr Tan took 6 hours to drve from Town A to Town B.
Mr Lm who started at the same time as Mr Tan took 4 hours to drive from Town B to Town A

When they met each other, they were 48km away from mid point of Town A and Town B

(a) Calculate the distance between Town A and Town B
(b) Calculate the speed of Mr Tan


Working
Time
Tan : Lim
6: 4


Ratio of Speed/Distance
Tan: Lim
6: 4
2:3

3u- 2u = 1u
Iu = 48km X 2 = 96km
5u= 96km x 5=480km

(b)480/6 = 80km/h

Is the working for (a) correct??


Thanks and regards,

Hi Herbie,

For part (a) I would have done as below. You answer is correct but I'm not able to follow the working.

When distance is constant (Town A to Town B)
Time ratio => Tan : Lim = 3 : 2
Speed ratio => Tan : Lim = 2 : 3

When they meet each other, they would have travelled the same time (time is constant). Tan would have travelled 2u and Lim travelled 3u when they met. Total distance between the 2 towns is 5u. So, Lim had travelled (5u/2 + 48km) before he met Tan.

For your working, I amended in red to make it clear.

a)\t3u – (5u/2) = 48km
1u = 48km x 2 = 96km
Distance between Town A and B = 5u = 5 x 96km = 480km

b) Speed of Mr Tan = 480km/6hrs = 80km/hr

[Dharma]

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

Hi Almighty,

Pls refer to Tianzhu's very clear illustration. Thanks

[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