Tutor MathsGuru: Ask me for your burning Maths questions!

[iFruit]

Let Distance walked by Toby = d, and his speed = s, time taken = d/s


Then distance walked by Samad = d + 20 and his speed = s +4

d/s = (d+20)/(s+4)---> (d+20)/d = (s+4)/s---> 1+20/d = 1+4/s

so 20/d = 4/s ---> d/s = 5 hours.

So Toby and Samad walked for 5 hours before they met.

Samad walked 10km in 1 hour (5-4), or his speed is 10km/h

beauty queen:

One more question mathgurus

i think an easy one?

Samad and Toby walked from Town A to Town B at the same time. Samad was faster than Toby by 4km/h. When Samad reached Town B in 4 hours, he immediately walked back to Town A. On the way back he met toby who was 10 km away from Town B. What was Samad's speed

[Vanilla Cake]

iFruit:

Let Distance walked by Toby = d, and his speed = s, time taken = d/s


Then distance walked by Samad = d + 20 and his speed = s +4

d/s = (d+20)/(s+4)---> (d+20)/d = (s+4)/s---> 1+20/d = 1+4/s

so 20/d = 4/s ---> d/s = 5 hours.

So Toby and Samad walked for 5 hours before they met.

Samad walked 10km in 1 hour (5-4), or his speed is 10km/h

beauty queen:

One more question mathgurus

i think an easy one?

Samad and Toby walked from Town A to Town B at the same time. Samad was faster than Toby by 4km/h. When Samad reached Town B in 4 hours, he immediately walked back to Town A. On the way back he met toby who was 10 km away from Town B. What was Samad's speed

Hi beauty queen,

Here's another http://www.onsponge.com/forum/35-thinkingmathonsponge/5226-p6-speed.html by Chris Rogers @ OnSponge forum for your speed question without using algebra.

[beauty queen]

hello once again a 3 mark question,


This is from henry park 2010 prelim p2 question 10. (sorry dont have the image available)

The figure below is made up of three squares of sides 8 cm 12 cm and 20cm. Find the shaded area.

[Dharma]

CJM:

Dharma:

[quote=\"CJM\"]A kettle has 420ml more water than a jug. When 150ml of water is poured from the jug into the kettle, thre are 4 times as much water in the kettle as the jug. How much water is there in the jug now ?

1u – 1p = 420 ------------- ( 1 )

Jug : 1p – 150
Kettle = 1u + 150

4p – 600 = 1u + 150
4p – 1u = 750 ------------ ( 2 )
( 1 ) + ( 2 )

3p = 1170
1p = 390
Amount of water in jug now = 1p – 150 = 390 – 150 = 240

Amount of water in jug now is 240 ml

Hi Dharma,

How to relate 1u & 1p ?
Need to draw model for this ?[/quote]1u = Amt of water in kettle at first
1p = Amt of water in jug at first

It is your choice whether you want to draw a model or not. Normally, my choice is not the model way.
Choose a method that you are comfortable with.

[Dharma]

CJM:

Dharma:

[quote=\"CJM\"]A kettle has 420ml more water than a jug. When 150ml of water is poured from the jug into the kettle, thre are 4 times as much water in the kettle as the jug. How much water is there in the jug now ?

1u – 1p = 420 ------------- ( 1 )

Jug : 1p – 150
Kettle = 1u + 150

4p – 600 = 1u + 150
4p – 1u = 750 ------------ ( 2 )
( 1 ) + ( 2 )

3p = 1170
1p = 390
Amount of water in jug now = 1p – 150 = 390 – 150 = 240

Amount of water in jug now is 240 ml

Hi Dharma,

How to relate 1u & 1p ?
Need to draw model for this ?[/quote]1u = Amt of water in kettle at first
1p = Amt of water in jug at first

It is your choice whether you want to draw a model or not. Normally, my choice is not the model way.
Choose a method that you are comfortable with.

[Vanilla Cake]

beauty queen:

hello once again a 3 mark question,


This is from henry park 2010 prelim p2 question 10. (sorry dont have the image available)

The figure below is made up of three squares of sides 8 cm 12 cm and 20cm. Find the shaded area.

This one is not easy to explain without a diagram.OK, let me try.
Label the area as A for the dotted area at the top left corner (The one drawn dotted on top of square - 12x12)
Label Area B as the triangle with base as 12+20=32 cm and height as 12 cm.

Total (A+B+Shaded)=12x20+1/2x28x20=520 cm²
Area of A=8x12=96 cm²
Area of B =1/2x12x32=192 cm²
(520-96-192) cm² = 232 cm²

Area of shaded area = 232 cm²

Are you a P6 student? Due to my heavy homework load, I am not able to scan the diagram.Sorry.

PS: It's better that you scan your diagram as most of us do not have the Maths papers on hand.Uncle Tianzhu had provided the guidelines on how to post diagrams/pictures in KSP forum, pls read them.

[CJM]

Vanilla Cake:

CJM:

[quote=\"Dharma\"]
1u – 1p = 420 ------------- ( 1 )

Jug : 1p – 150
Kettle = 1u + 150

4p – 600 = 1u + 150
4p – 1u = 750 ------------ ( 2 )
( 1 ) + ( 2 )

3p = 1170
1p = 390
Amount of water in jug now = 1p – 150 = 390 – 150 = 240

Amount of water in jug now is 240 ml

Hi Dharma,

How to relate 1u & 1p ?
Need to draw model for this ?

Hi CJM,
Is this P4 Maths? While waiting for Uncle Dharma's reply, here's my suggested model solution for your review:

In the end
K: [][150][420][150]
J: [][150]

[150] must be in dotted form. I use red colour to represent it in dotted form.

4 times as much water in the kettle as the jug means 4 times of J=K.
4 units of J = 1 unit of K
4[]=[]+150+420+150
3[]=720
[]=240

1 unit of [] of J =240 ml ie Amount of water in the jug now = 240 ml

Hope this helps.
[/quote]Hi Vanilla cake,

Yes this is P4 question.

My boy drew the model same as what u hv drawn except that he did not define one of the unit in K as 150 instead he put the total of 3 units as 150 and 420 only :

K: [][150][420][ ]

3u : (420 + 150) /3

Can u pls advise why need to add another 150 to K ?

Thanks : )

[Vanilla Cake]

CJM:

Can u pls advise why need to add another 150 to K ?

Because the kettle received 150 ml of water from the jug.

[Hiroii-kun]

Dear gurus, please help with this qn.


There are 2 bags of stones labeled A & B. In bag A, there are 350 black stones and 500 white stones. In bag B, there are 400 black stones and 100 white stones. How many black and white stones should be transferred from bag B to bag A so that 50% of stones in bag A and 75% of stones in bag B are black?

[Vanilla Cake]

Hiroii-kun:

Dear gurus, please help with this qn.


There are 2 bags of stones labeled A & B. In bag A, there are 350 black stones and 500 white stones. In bag B, there are 400 black stones and 100 white stones. How many black and white stones should be transferred from bag B to bag A so that 50% of stones in bag A and 75% of stones in bag B are black?

This question is similar to RGPS 2009 P6 SA1 Paper 2 Q18 and pls refer to http://psle2010a.blogspot.com/2010/04/percentage-p6-2009-sa1-p2-rgs-q18_5512.html for reference while waiting for others to post their solutions.

Need to go to school now and sorry that I don't have time to post the solution for this question.The answer is 175 black and 25 white stones should be transferred from bag B to bag A so that 50% of stones in bag A and 75% of stones in bag B are black.

Hope that others like Uncle Dharma will help to check my answers and post the solution.